Vulnerability-Lookup

CVE-2026-77680 (GCVE-0-2026-77680)

Vulnerability from cvelistv5 – Published: 2026-08-25 20:36 – Updated: 2026-08-26 12:43

Title

Libsoup3: libsoup: quadratic cpu denial of service in http range coalescing after cve-2025-32907 fix

Summary

An algorithmic complexity flaw exists in libsoup's HTTP Range header processing that persists after the CVE-2025-32907 fix. CVE-2025-32907 addressed memory amplification when a client repeated the same range many times in a single Range header. Commit 9bb92f7a corrected merge correctness in soup_message_headers_get_ranges_internal() in libsoup/soup-message-headers.c, but the coalescing loop still removes merged ranges using g_array_remove_index() for each coalesced element. Because GArray is contiguous, each mid-array removal performs an O(N) memmove. When many identical satisfiable ranges are supplied (for example bytes=0-0 repeated thousands of times), the loop performs O(N²) work coalescing them into a single range. The vulnerable path is reachable server-side from handle_partial_get() in libsoup/server/http1/soup-server-message-io-http1.c when a SoupServer handler returns HTTP 200 with a non-empty body. No authentication is required. The number of ranges is bounded only by the maximum request header size (~100 KiB), allowing roughly 25,000 ranges per request. Reporter measurements on libsoup HEAD containing the CVE-2025-32907 fix show ~90 ms single-core CPU per such request at the wire maximum, blocking the server's event loop for that duration. This is a CPU exhaustion / availability issue only. No memory corruption or information disclosure occurs. Affected: libsoup versions containing the CVE-2025-32907 fix but not merge request !550. Fixed upstream: MR !550 merged 2026-08-20, replacing per-element removal with O(N) in-place compaction and rejecting Range headers requesting more than 200 ranges. Upstream report: https://gitlab.gnome.org/GNOME/libsoup/-/issues/538 Related: CVE-2025-32907

Severity

5.3 (Medium)


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

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-26 12:38 UTC

CWE

CWE-407 - Inefficient Algorithmic Complexity

Assigner

redhat redhat root

References

5 references

URL	Tags
https://access.redhat.com/security/cve/CVE-2025-32907	technical-descriptionx_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-77680	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2520892	issue-trackingx_refsource_REDHAT
https://gitlab.gnome.org/GNOME/libsoup/-/issues/538
https://gitlab.gnome.org/GNOME/libsoup/-/merge_re…

Impacted products

1 product

Vendor	Product	Version	CPE status
Red Hat	Red Hat Enterprise Linux 10	cpe:/o:redhat:enterprise_linux:10

Date Public

2026-08-21 00:00

Credits

Red Hat would like to thank Jianqiang (Stark) Li for reporting this issue.

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-77680

Vulnerability from fkie_nvd - Published: 2026-08-25 21:17 - Updated: 2026-08-26 13:19

Severity

5.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Summary

References

	URL	Tags
	secalert@redhat.com	https://access.redhat.com/security/cve/CVE-2025-32907
	secalert@redhat.com	https://access.redhat.com/security/cve/CVE-2026-77680
	secalert@redhat.com	https://bugzilla.redhat.com/show_bug.cgi?id=2520892
	secalert@redhat.com	https://gitlab.gnome.org/GNOME/libsoup/-/issues/538
	secalert@redhat.com	https://gitlab.gnome.org/GNOME/libsoup/-/merge_requests/550
	134c704f-9b21-4f2e-91b3-4a467353bcc0	https://gitlab.gnome.org/GNOME/libsoup/-/issues/538

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-26T12:38:58.296657Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-25T21:17:46.243",
  "references": [
    {
      "source": "secalert@redhat.com",
      "url": "https://access.redhat.com/security/cve/CVE-2025-32907"
    },
    {
      "source": "secalert@redhat.com",
      "url": "https://access.redhat.com/security/cve/CVE-2026-77680"
    },
    {
      "source": "secalert@redhat.com",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2520892"
    },
    {
      "source": "secalert@redhat.com",
      "url": "https://gitlab.gnome.org/GNOME/libsoup/-/issues/538"
    },
    {
      "source": "secalert@redhat.com",
      "url": "https://gitlab.gnome.org/GNOME/libsoup/-/merge_requests/550"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://gitlab.gnome.org/GNOME/libsoup/-/issues/538"
    }
  ],
  "sourceIdentifier": "secalert@redhat.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-407"
        }
      ],
      "source": "secalert@redhat.com",
      "type": "Secondary"
    }
  ]
}

GHSA-9M98-W4QJ-8F6Q

Vulnerability from github – Published: 2026-08-25 21:31 – Updated: 2026-08-25 21:31

Details

An algorithmic complexity flaw exists in libsoup's HTTP Range header processing that persists after the CVE-2025-32907 fix.

CVE-2025-32907 addressed memory amplification when a client repeated the same range many times in a single Range header. Commit 9bb92f7a corrected merge correctness in soup_message_headers_get_ranges_internal() in libsoup/soup-message-headers.c, but the coalescing loop still removes merged ranges using g_array_remove_index() for each coalesced element. Because GArray is contiguous, each mid-array removal performs an O(N) memmove. When many identical satisfiable ranges are supplied (for example bytes=0-0 repeated thousands of times), the loop performs O(N²) work coalescing them into a single range.

The vulnerable path is reachable server-side from handle_partial_get() in libsoup/server/http1/soup-server-message-io-http1.c when a SoupServer handler returns HTTP 200 with a non-empty body. No authentication is required. The number of ranges is bounded only by the maximum request header size (~100 KiB), allowing roughly 25,000 ranges per request. Reporter measurements on libsoup HEAD containing the CVE-2025-32907 fix show ~90 ms single-core CPU per such request at the wire maximum, blocking the server's event loop for that duration.

This is a CPU exhaustion / availability issue only. No memory corruption or information disclosure occurs.

Affected: libsoup versions containing the CVE-2025-32907 fix but not merge request !550. Fixed upstream: MR !550 merged 2026-08-20, replacing per-element removal with O(N) in-place compaction and rejecting Range headers requesting more than 200 ranges. Upstream report: https://gitlab.gnome.org/GNOME/libsoup/-/issues/538 Related: CVE-2025-32907

Severity

5.3 (Medium)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-77680"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-407"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-25T21:17:46Z",
    "severity": "MODERATE"
  },
  "details": "An algorithmic complexity flaw exists in libsoup\u0027s HTTP Range header processing that persists after the CVE-2025-32907 fix.\n\nCVE-2025-32907 addressed memory amplification when a client repeated the same range many times in a single Range header. Commit 9bb92f7a corrected merge correctness in soup_message_headers_get_ranges_internal() in libsoup/soup-message-headers.c, but the coalescing loop still removes merged ranges using g_array_remove_index() for each coalesced element. Because GArray is contiguous, each mid-array removal performs an O(N) memmove. When many identical satisfiable ranges are supplied (for example bytes=0-0 repeated thousands of times), the loop performs O(N\u00b2) work coalescing them into a single range.\n\nThe vulnerable path is reachable server-side from handle_partial_get() in libsoup/server/http1/soup-server-message-io-http1.c when a SoupServer handler returns HTTP 200 with a non-empty body. No authentication is required. The number of ranges is bounded only by the maximum request header size (~100 KiB), allowing roughly 25,000 ranges per request. Reporter measurements on libsoup HEAD containing the CVE-2025-32907 fix show ~90 ms single-core CPU per such request at the wire maximum, blocking the server\u0027s event loop for that duration.\n\nThis is a CPU exhaustion / availability issue only. No memory corruption or information disclosure occurs.\n\nAffected: libsoup versions containing the CVE-2025-32907 fix but not merge request !550.\nFixed upstream: MR !550 merged 2026-08-20, replacing per-element removal with O(N) in-place compaction and rejecting Range headers requesting more than 200 ranges.\nUpstream report: https://gitlab.gnome.org/GNOME/libsoup/-/issues/538\nRelated: CVE-2025-32907",
  "id": "GHSA-9m98-w4qj-8f6q",
  "modified": "2026-08-25T21:31:32Z",
  "published": "2026-08-25T21:31:32Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-77680"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2025-32907"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-77680"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2520892"
    },
    {
      "type": "WEB",
      "url": "https://gitlab.gnome.org/GNOME/libsoup/-/issues/538"
    },
    {
      "type": "WEB",
      "url": "https://gitlab.gnome.org/GNOME/libsoup/-/merge_requests/550"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ]
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

CVE-2026-77680 (GCVE-0-2026-77680)

FKIE_CVE-2026-77680

GHSA-9M98-W4QJ-8F6Q

Tags

Sightings

Nomenclature