Vulnerability-Lookup

alsa-2026:22551

Vulnerability from osv_almalinux

Published

2026-06-02 00:00

Modified

2026-06-04 09:27

Summary

Moderate: mod_http2 security update

Details

The mod_h2 Apache httpd module implements the HTTP2 protocol (h2+h2c) on top of libnghttp2 for httpd 2.4 servers.

Security Fix(es):

httpd: Apache HTTP Server: HTTP/2 DoS by Memory Increase (CVE-2025-53020)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

References

URL

Type

	https://access.redhat.com/errata/RHSA-2026:22551	ADVISORY
	https://access.redhat.com/security/cve/CVE-2025-53020	REPORT
	https://bugzilla.redhat.com/2379343	REPORT
	https://errata.almalinux.org/9/ALSA-2026-22551.html	ADVISORY

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "AlmaLinux:9",
        "name": "mod_http2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.0.26-6.el9_8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "The mod_h2 Apache httpd module implements the HTTP2 protocol (h2+h2c) on top of libnghttp2 for httpd 2.4 servers.  \n\nSecurity Fix(es):  \n\n  * httpd: Apache HTTP Server: HTTP/2 DoS by Memory Increase (CVE-2025-53020)\n\n\nFor more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.\n",
  "id": "ALSA-2026:22551",
  "modified": "2026-06-04T09:27:30Z",
  "published": "2026-06-02T00:00:00Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:22551"
    },
    {
      "type": "REPORT",
      "url": "https://access.redhat.com/security/cve/CVE-2025-53020"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/2379343"
    },
    {
      "type": "ADVISORY",
      "url": "https://errata.almalinux.org/9/ALSA-2026-22551.html"
    }
  ],
  "related": [
    "CVE-2025-53020"
  ],
  "summary": "Moderate: mod_http2 security update"
}

CVE-2025-53020 (GCVE-0-2025-53020)

Vulnerability from cvelistv5 – Published: 2025-07-10 16:59 – Updated: 2025-11-04 21:11

Title

Apache HTTP Server: HTTP/2 DoS by Memory Increase

Summary

Late Release of Memory after Effective Lifetime vulnerability in Apache HTTP Server. This issue affects Apache HTTP Server: from 2.4.17 up to 2.4.63. Users are recommended to upgrade to version 2.4.64, which fixes the issue.

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-401 - Missing Release of Memory after Effective Lifetime

Assigner

apache

References

3 references

URL	Tags
https://httpd.apache.org/security/vulnerabilities…	vendor-advisory
https://lists.debian.org/debian-lts-announce/2025…
http://www.openwall.com/lists/oss-security/2025/0…

Impacted products

1 product

Vendor	Product	Version
Apache Software Foundation	Apache HTTP Server	Affected: 2.4.17 , ≤ 2.4.63 (semver)

Credits

Gal Bar Nahum

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 7.5,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "NONE",
              "integrityImpact": "NONE",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2025-53020",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-07-11T16:05:41.419033Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-07-15T19:56:07.763Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2025-11-04T21:11:43.692Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
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        },
        "references": [
          {
            "url": "https://lists.debian.org/debian-lts-announce/2025/08/msg00009.html"
          },
          {
            "url": "http://www.openwall.com/lists/oss-security/2025/07/10/10"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
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          "product": "Apache HTTP Server",
          "vendor": "Apache Software Foundation",
          "versions": [
            {
              "lessThanOrEqual": "2.4.63",
              "status": "affected",
              "version": "2.4.17",
              "versionType": "semver"
            }
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        }
      ],
      "credits": [
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          "lang": "en",
          "type": "finder",
          "value": "Gal Bar Nahum"
        }
      ],
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            }
          ],
          "value": "Late Release of Memory after Effective Lifetime vulnerability in Apache HTTP Server.\n\nThis issue affects Apache HTTP Server: from 2.4.17 up to 2.4.63.\n\nUsers are recommended to upgrade to version 2.4.64, which fixes the issue."
        }
      ],
      "metrics": [
        {
          "other": {
            "content": {
              "text": "moderate"
            },
            "type": "Textual description of severity"
          }
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      "problemTypes": [
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        "dateUpdated": "2025-07-10T16:59:06.340Z",
        "orgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
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      },
      "references": [
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          "url": "https://httpd.apache.org/security/vulnerabilities_24.html"
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      "source": {
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          "time": "2025-06-18T09:19:00.000Z",
          "value": "reported"
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          "time": "2025-06-19T09:20:00.000Z",
          "value": "fix developed"
        },
        {
          "lang": "en",
          "time": "2025-07-07T00:00:00.000Z",
          "value": "2.4.x revision 1927046"
        }
      ],
      "title": "Apache HTTP Server: HTTP/2 DoS by Memory Increase",
      "x_generator": {
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  },
  "cveMetadata": {
    "assignerOrgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
    "assignerShortName": "apache",
    "cveId": "CVE-2025-53020",
    "datePublished": "2025-07-10T16:59:06.340Z",
    "dateReserved": "2025-06-24T07:13:19.552Z",
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}

Sightings

Author	Source	Type	Date	Other

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

Detection rules are retrieved from Rulezet.

Action not permitted

alsa-2026:22551

Vulnerability from osv_almalinux

CVE-2025-53020 (GCVE-0-2025-53020)

Tags

Sightings

Nomenclature