CVE-2025-21910 (GCVE-0-2025-21910)

Vulnerability from cvelistv5 – Published: 2025-04-01 15:40 – Updated: 2026-05-11 21:08
VLAI
Title
wifi: cfg80211: regulatory: improve invalid hints checking
Summary
In the Linux kernel, the following vulnerability has been resolved: wifi: cfg80211: regulatory: improve invalid hints checking Syzbot keeps reporting an issue [1] that occurs when erroneous symbols sent from userspace get through into user_alpha2[] via regulatory_hint_user() call. Such invalid regulatory hints should be rejected. While a sanity check from commit 47caf685a685 ("cfg80211: regulatory: reject invalid hints") looks to be enough to deter these very cases, there is a way to get around it due to 2 reasons. 1) The way isalpha() works, symbols other than latin lower and upper letters may be used to determine a country/domain. For instance, greek letters will also be considered upper/lower letters and for such characters isalpha() will return true as well. However, ISO-3166-1 alpha2 codes should only hold latin characters. 2) While processing a user regulatory request, between reg_process_hint_user() and regulatory_hint_user() there happens to be a call to queue_regulatory_request() which modifies letters in request->alpha2[] with toupper(). This works fine for latin symbols, less so for weird letter characters from the second part of _ctype[]. Syzbot triggers a warning in is_user_regdom_saved() by first sending over an unexpected non-latin letter that gets malformed by toupper() into a character that ends up failing isalpha() check. Prevent this by enhancing is_an_alpha2() to ensure that incoming symbols are latin letters and nothing else. [1] Syzbot report: ------------[ cut here ]------------ Unexpected user alpha2: A� WARNING: CPU: 1 PID: 964 at net/wireless/reg.c:442 is_user_regdom_saved net/wireless/reg.c:440 [inline] WARNING: CPU: 1 PID: 964 at net/wireless/reg.c:442 restore_alpha2 net/wireless/reg.c:3424 [inline] WARNING: CPU: 1 PID: 964 at net/wireless/reg.c:442 restore_regulatory_settings+0x3c0/0x1e50 net/wireless/reg.c:3516 Modules linked in: CPU: 1 UID: 0 PID: 964 Comm: kworker/1:2 Not tainted 6.12.0-rc5-syzkaller-00044-gc1e939a21eb1 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: events_power_efficient crda_timeout_work RIP: 0010:is_user_regdom_saved net/wireless/reg.c:440 [inline] RIP: 0010:restore_alpha2 net/wireless/reg.c:3424 [inline] RIP: 0010:restore_regulatory_settings+0x3c0/0x1e50 net/wireless/reg.c:3516 ... Call Trace: <TASK> crda_timeout_work+0x27/0x50 net/wireless/reg.c:542 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa65/0x1850 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK>
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 09d989d179d0c679043556dda77c51b41a2dae7e , < 62b1a9bbfebba4b4c2bb6c1ede9ef7ecee7a9ff6 (git)
Affected: 09d989d179d0c679043556dda77c51b41a2dae7e , < da3f599517ef2ea851208df3229d07728d238dc5 (git)
Affected: 09d989d179d0c679043556dda77c51b41a2dae7e , < 6a5e3b23054cee3b92683d1467e3fa83921f5622 (git)
Affected: 09d989d179d0c679043556dda77c51b41a2dae7e , < f4112cb477c727a65787a4065a75ca593bb5b2f4 (git)
Affected: 09d989d179d0c679043556dda77c51b41a2dae7e , < 35ef07112b61b06eb30683a6563c9f6378c02476 (git)
Affected: 09d989d179d0c679043556dda77c51b41a2dae7e , < be7c5f00aa7f1344293e4d48d0e12be83a2f223d (git)
Affected: 09d989d179d0c679043556dda77c51b41a2dae7e , < 17aa34c84867f6cd181a5743e1c647e7766962a6 (git)
Affected: 09d989d179d0c679043556dda77c51b41a2dae7e , < 59b348be7597c4a9903cb003c69e37df20c04a30 (git)
guessed Create a notification for this product.
Linux Linux Affected: 2.6.34
Unaffected: 0 , < 2.6.34 (semver)
Unaffected: 5.4.291 , ≤ 5.4.* (semver)
Unaffected: 5.10.235 , ≤ 5.10.* (semver)
Unaffected: 5.15.179 , ≤ 5.15.* (semver)
Unaffected: 6.1.131 , ≤ 6.1.* (semver)
Unaffected: 6.6.83 , ≤ 6.6.* (semver)
Unaffected: 6.12.19 , ≤ 6.12.* (semver)
Unaffected: 6.13.7 , ≤ 6.13.* (semver)
Unaffected: 6.14 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "32865E5C-8AE1-4D3D-A64D-299039694A88",
                    "versionEndExcluding": "6.12.19",
                    "versionStartIncluding": "6.7",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "842F5A44-3E71-4546-B4FD-43B0ACE3F32B",
                    "versionEndExcluding": "6.13.7",
                    "versionStartIncluding": "6.13",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:*",
                    "matchCriteriaId": "186716B6-2B66-4BD0-852E-D48E71C0C85F",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:*",
                    "matchCriteriaId": "0D3E781C-403A-498F-9DA9-ECEE50F41E75",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc3:*:*:*:*:*:*",
                    "matchCriteriaId": "66619FB8-0AAF-4166-B2CF-67B24143261D",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc4:*:*:*:*:*:*",
                    "matchCriteriaId": "D3D6550E-6679-4560-902D-AF52DCFE905B",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc5:*:*:*:*:*:*",
                    "matchCriteriaId": "45B90F6B-BEC7-4D4E-883A-9DBADE021750",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: cfg80211: regulatory: improve invalid hints checking\n\nSyzbot keeps reporting an issue [1] that occurs when erroneous symbols\nsent from userspace get through into user_alpha2[] via\nregulatory_hint_user() call. Such invalid regulatory hints should be\nrejected.\n\nWhile a sanity check from commit 47caf685a685 (\"cfg80211: regulatory:\nreject invalid hints\") looks to be enough to deter these very cases,\nthere is a way to get around it due to 2 reasons.\n\n1) The way isalpha() works, symbols other than latin lower and\nupper letters may be used to determine a country/domain.\nFor instance, greek letters will also be considered upper/lower\nletters and for such characters isalpha() will return true as well.\nHowever, ISO-3166-1 alpha2 codes should only hold latin\ncharacters.\n\n2) While processing a user regulatory request, between\nreg_process_hint_user() and regulatory_hint_user() there happens to\nbe a call to queue_regulatory_request() which modifies letters in\nrequest-\u003ealpha2[] with toupper(). This works fine for latin symbols,\nless so for weird letter characters from the second part of _ctype[].\n\nSyzbot triggers a warning in is_user_regdom_saved() by first sending\nover an unexpected non-latin letter that gets malformed by toupper()\ninto a character that ends up failing isalpha() check.\n\nPrevent this by enhancing is_an_alpha2() to ensure that incoming\nsymbols are latin letters and nothing else.\n\n[1] Syzbot report:\n------------[ cut here ]------------\nUnexpected user alpha2: A\ufffd\nWARNING: CPU: 1 PID: 964 at net/wireless/reg.c:442 is_user_regdom_saved net/wireless/reg.c:440 [inline]\nWARNING: CPU: 1 PID: 964 at net/wireless/reg.c:442 restore_alpha2 net/wireless/reg.c:3424 [inline]\nWARNING: CPU: 1 PID: 964 at net/wireless/reg.c:442 restore_regulatory_settings+0x3c0/0x1e50 net/wireless/reg.c:3516\nModules linked in:\nCPU: 1 UID: 0 PID: 964 Comm: kworker/1:2 Not tainted 6.12.0-rc5-syzkaller-00044-gc1e939a21eb1 #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024\nWorkqueue: events_power_efficient crda_timeout_work\nRIP: 0010:is_user_regdom_saved net/wireless/reg.c:440 [inline]\nRIP: 0010:restore_alpha2 net/wireless/reg.c:3424 [inline]\nRIP: 0010:restore_regulatory_settings+0x3c0/0x1e50 net/wireless/reg.c:3516\n...\nCall Trace:\n \u003cTASK\u003e\n crda_timeout_work+0x27/0x50 net/wireless/reg.c:542\n process_one_work kernel/workqueue.c:3229 [inline]\n process_scheduled_works+0xa65/0x1850 kernel/workqueue.c:3310\n worker_thread+0x870/0xd30 kernel/workqueue.c:3391\n kthread+0x2f2/0x390 kernel/kthread.c:389\n ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244\n \u003c/TASK\u003e"
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: wifi: cfg80211: regulatory: improve invalid hints checking Syzbot sigue reportando un problema [1] que ocurre cuando s\u00edmbolos err\u00f3neos enviados desde el espacio de usuario se introducen en user_alpha2[] mediante la llamada regulatory_hint_user(). Estas sugerencias regulatorias inv\u00e1lidas deben rechazarse. Si bien una comprobaci\u00f3n de seguridad del commit 47caf685a685 (\"cfg80211: regulatory: reject invalid hints\") parece ser suficiente para evitar estos casos, existe una forma de evitarla por dos razones: 1) El funcionamiento de isalpha() permite usar s\u00edmbolos distintos de las letras latinas may\u00fasculas y min\u00fasculas para determinar un pa\u00eds o dominio. Por ejemplo, las letras griegas tambi\u00e9n se considerar\u00e1n may\u00fasculas y min\u00fasculas, y para estos caracteres isalpha() tambi\u00e9n devolver\u00e1 verdadero. Sin embargo, los c\u00f3digos ISO-3166-1 alpha2 solo deben contener caracteres latinos. 2) Al procesar una solicitud regulatoria de usuario, entre reg_process_hint_user() y regulatory_hint_user() se produce una llamada a queue_regulatory_request() que modifica las letras en request-\u0026gt;alpha2[] con toupper(). Esto funciona correctamente con s\u00edmbolos latinos, pero no tanto con caracteres de letras extra\u00f1as de la segunda parte de _ctype[]. Syzbot genera una advertencia en is_user_regdom_saved() al enviar primero una letra no latina inesperada que toupper() malforma en un car\u00e1cter que falla la comprobaci\u00f3n de isalpha(). Para evitar esto, mejore is_an_alpha2() para garantizar que los s\u00edmbolos entrantes sean \u00fanicamente letras latinas. [1] Informe de Syzbot: ------------[ cortar aqu\u00ed ]------------ Usuario inesperado alpha2: A? ADVERTENCIA: CPU: 1 PID: 964 en net/wireless/reg.c:442 is_user_regdom_saved net/wireless/reg.c:440 [en l\u00ednea] ADVERTENCIA: CPU: 1 PID: 964 en net/wireless/reg.c:442 restore_alpha2 net/wireless/reg.c:3424 [en l\u00ednea] ADVERTENCIA: CPU: 1 PID: 964 en net/wireless/reg.c:442 restore_regulatory_settings+0x3c0/0x1e50 net/wireless/reg.c:3516 M\u00f3dulos vinculados: CPU: 1 UID: 0 PID: 964 Comm: kworker/1:2 No contaminado 6.12.0-rc5-syzkaller-00044-gc1e939a21eb1 #0 Nombre del hardware: Google Google Compute Engine/Google Compute Engine, BIOS Google 13/09/2024 Cola de trabajo: events_power_efficient crda_timeout_work RIP: 0010:is_user_regdom_saved net/wireless/reg.c:440 [en l\u00ednea] RIP: 0010:restore_alpha2 net/wireless/reg.c:3424 [en l\u00ednea] RIP: 0010:restore_regulatory_settings+0x3c0/0x1e50 net/wireless/reg.c:3516 ... Rastreo de llamadas:  crda_timeout_work+0x27/0x50 net/wireless/reg.c:542 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa65/0x1850 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244  "
          }
        ],
        "id": "CVE-2025-21910",
        "lastModified": "2026-06-17T08:44:35.277",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 5.5,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 3.6,
              "source": "nvd@nist.gov",
              "type": "Primary"
            }
          ]
        },
        "published": "2025-04-01T16:15:21.550",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/17aa34c84867f6cd181a5743e1c647e7766962a6"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/35ef07112b61b06eb30683a6563c9f6378c02476"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/59b348be7597c4a9903cb003c69e37df20c04a30"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/62b1a9bbfebba4b4c2bb6c1ede9ef7ecee7a9ff6"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/6a5e3b23054cee3b92683d1467e3fa83921f5622"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/be7c5f00aa7f1344293e4d48d0e12be83a2f223d"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/da3f599517ef2ea851208df3229d07728d238dc5"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/f4112cb477c727a65787a4065a75ca593bb5b2f4"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Modified",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "NVD-CWE-noinfo"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-06-30T10:30:28+00:00",
      "cve": "CVE-2025-21910",
      "id": "CVE-2025-21910",
      "initial_release_date": "2025-04-01T00:00:00+00:00",
      "product_status:known_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: wifi: cfg80211: regulatory: improve invalid hints checking",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-21910.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-23T00:46:57Z",
      "cve": "CVE-2025-21910",
      "id": "CVE-2025-21910",
      "initial_release_date": "2026-06-05T03:31:18Z",
      "product_status:known_affected": "722",
      "product_status:known_not_affected": "43",
      "product_status:recommended": "424",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2025-21910",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2025-21910.json",
      "version": "9"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.