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FKIE_CVE-2021-26937

Vulnerability from fkie_nvd - Published: 2021-02-09 20:15 - Updated: 2026-06-17 03:44
Severity
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
encoding.c in GNU Screen through 4.8.0 allows remote attackers to cause a denial of service (invalid write access and application crash) or possibly have unspecified other impact via a crafted UTF-8 character sequence.
References
cve@mitre.orghttp://www.openwall.com/lists/oss-security/2021/02/09/8Exploit, Mailing List, Third Party Advisory
cve@mitre.orghttps://ftp.gnu.org/gnu/screen/Product
cve@mitre.orghttps://lists.debian.org/debian-lts-announce/2021/02/msg00031.htmlMailing List, Third Party Advisory
cve@mitre.orghttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GNWBOIDEPOEQS5RMQVMFKHKXJCGNYWBL/
cve@mitre.orghttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JJWLXP45POUUYBJRRWPVAWNZDJTLYWVM/
cve@mitre.orghttps://lists.gnu.org/archive/html/screen-devel/2021-02/msg00000.htmlExploit, Mailing List, Vendor Advisory
cve@mitre.orghttps://security.gentoo.org/glsa/202105-11Third Party Advisory
cve@mitre.orghttps://www.debian.org/security/2021/dsa-4861Third Party Advisory
cve@mitre.orghttps://www.openwall.com/lists/oss-security/2021/02/09/3Exploit, Mailing List, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108http://www.openwall.com/lists/oss-security/2021/02/09/8Exploit, Mailing List, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://ftp.gnu.org/gnu/screen/Product
af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2021/02/msg00031.htmlMailing List, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GNWBOIDEPOEQS5RMQVMFKHKXJCGNYWBL/
af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JJWLXP45POUUYBJRRWPVAWNZDJTLYWVM/
af854a3a-2127-422b-91ae-364da2661108https://lists.gnu.org/archive/html/screen-devel/2021-02/msg00000.htmlExploit, Mailing List, Vendor Advisory
af854a3a-2127-422b-91ae-364da2661108https://security.gentoo.org/glsa/202105-11Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://security.netapp.com/advisory/ntap-20250509-0004/
af854a3a-2127-422b-91ae-364da2661108https://www.debian.org/security/2021/dsa-4861Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://www.openwall.com/lists/oss-security/2021/02/09/3Exploit, Mailing List, Third Party Advisory
Impacted products
Vendor Product Version
gnu screen *
debian debian_linux 9.0
debian debian_linux 10.0
fedoraproject fedora 32
fedoraproject fedora 33
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "source": "cve@mitre.org"
    }
  ],
  "configurations": [
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      "nodes": [
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              "matchCriteriaId": "F31304B8-5E0C-4BA0-89F6-E2D0CA54A0AC",
              "versionEndIncluding": "4.8.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
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              "vulnerable": true
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "encoding.c in GNU Screen through 4.8.0 allows remote attackers to cause a denial of service (invalid write access and application crash) or possibly have unspecified other impact via a crafted UTF-8 character sequence."
    },
    {
      "lang": "es",
      "value": "El archivo encoding.c en GNU Screen versiones hasta 4.8.0, permite a atacantes remotos causar una denegaci\u00f3n de servicio (acceso de escritura no v\u00e1lido y bloqueo de la aplicaci\u00f3n) o posiblemente tener otro impacto no especificado por medio de una secuencia de caracteres UTF-8 dise\u00f1ada"
    }
  ],
  "id": "CVE-2021-26937",
  "lastModified": "2026-06-17T03:44:02.737",
  "metrics": {
    "cvssMetricV2": [
      {
        "acInsufInfo": false,
        "baseSeverity": "HIGH",
        "cvssData": {
          "accessComplexity": "LOW",
          "accessVector": "NETWORK",
          "authentication": "NONE",
          "availabilityImpact": "PARTIAL",
          "baseScore": 7.5,
          "confidentialityImpact": "PARTIAL",
          "integrityImpact": "PARTIAL",
          "vectorString": "AV:N/AC:L/Au:N/C:P/I:P/A:P",
          "version": "2.0"
        },
        "exploitabilityScore": 10.0,
        "impactScore": 6.4,
        "obtainAllPrivilege": false,
        "obtainOtherPrivilege": false,
        "obtainUserPrivilege": false,
        "source": "nvd@nist.gov",
        "type": "Primary",
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
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        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
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        "impactScore": 5.9,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
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  },
  "published": "2021-02-09T20:15:14.910",
  "references": [
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      "source": "cve@mitre.org",
      "tags": [
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  "sourceIdentifier": "cve@mitre.org",
  "vulnStatus": "Modified",
  "weaknesses": [
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      "description": [
        {
          "lang": "en",
          "value": "CWE-88"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



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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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  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
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  • 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.


Detection rules are retrieved from Rulezet.


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.