CVE-2026-77680

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

Score 5.3 from GitHub Security Advisory published 2026-08-25. A secondary CVSS source baseline 5.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this weekElevated
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 5.3Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

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

CVSS v3
5.3
EG Score
5.3MEDIUMmedium confidence
EG Risk
55
EG Risk 55/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity53% × 45%
Exploitation40% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.3%
EPSS %ILE
25th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 25, 2026

Last Modified

August 28, 2026

Advisory Details (5)

Auto-updated Aug 25, 2026
🔬 Proof of concept available. Patch available. Sources: redhat.
generic

message-headers: Fix Range and Content-Range parsing (!550) · Merge requests · GNOME / libsoup · GitLab

https://gitlab.gnome.org/GNOME/libsoup/-/merge_requests/550
generic🟡 PoC Available

(CVE-2026-77680) Incomplete fix for CVE-2025-32907: Range-coalescing DoS persists as O(N²) CPU exhaustion on patched libsoup (#538) · Issues · GNOME / libsoup · GitLab

https://gitlab.gnome.org/GNOME/libsoup/-/issues/538
redhat

Bug Access Denied

https://bugzilla.redhat.com/show_bug.cgi?id=2520892
redhatMentions a patch (unverified)

CVE-2026-77680 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2026-77680
redhatMentions a patch (unverified)

CVE-2025-32907 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2025-32907

Vendor Advisories for CVE-2026-77680(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibsoup2.4-doc (2.62.1-1ubuntu0.4+esm9) @ bionic2026-10-10ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(5 across 3 ecosystems)
Debian:12(2)
PackageVulnerable rangeFix by version rangeDependents
libsoup2.42.74.3-1 ... 2.74.3-9 (16 versions)
  • every version on: no fix on record
—
libsoup33.2.2-2 ... 3.6.6-1 (35 versions)
  • every version on: no fix on record
—
Debian:13(2)
PackageVulnerable rangeFix by version rangeDependents
libsoup2.42.74.3-10.1, 2.74.3-11
  • every version on: no fix on record
—
libsoup33.6.5-3 ... 3.6.6-1 (8 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
libsoup33.6.5-3 ... 3.6.6-1 (8 versions)
  • every version on: no fix on record
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 24× in last 7d / 87× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 132 total refreshes for this CVE.

  1. 2026-10-10 11:11 UTCEG score recompute
  2. 2026-10-10 11:11 UTCVendor advisory
  3. 2026-10-10 11:11 UTCGHSA enrichment
  4. 2026-10-09 20:07 UTCEPSS rescore
  5. 2026-10-09 03:42 UTCEG score recompute
  6. 2026-10-09 03:42 UTCVendor advisory
  7. 2026-10-09 03:42 UTCGHSA enrichment
  8. 2026-10-08 17:13 UTCEPSS rescore
  9. 2026-10-08 02:17 UTCEG score recompute
  10. 2026-10-08 02:17 UTCVendor advisory
  11. 2026-10-08 02:17 UTCGHSA enrichment
  12. 2026-10-07 23:48 UTCEPSS rescore
  13. 2026-10-07 02:11 UTCEG score recompute
  14. 2026-10-07 02:11 UTCVendor advisory
  15. 2026-10-07 02:11 UTCGHSA enrichment
  16. 2026-10-06 15:18 UTCEPSS rescore
  17. 2026-10-06 02:49 UTCEG score recompute
  18. 2026-10-06 02:49 UTCGHSA enrichment
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  20. 2026-10-05 03:46 UTCEG score recompute
  21. 2026-10-05 03:46 UTCGHSA enrichment
  22. 2026-10-04 23:22 UTCEPSS rescore
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  24. 2026-10-04 04:30 UTCGHSA enrichment
  25. 2026-10-03 14:26 UTCEPSS rescore
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  1. 2026-10-03 05:27 UTCEG score recompute
  2. 2026-10-03 05:27 UTCGHSA enrichment
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  4. 2026-10-02 06:24 UTCGHSA enrichment
  5. 2026-10-01 19:50 UTCEPSS rescore
  6. 2026-10-01 05:34 UTCEG score recompute
  7. 2026-10-01 05:34 UTCGHSA enrichment
  8. 2026-09-30 06:22 UTCEG score recompute
  9. 2026-09-30 06:22 UTCGHSA enrichment
  10. 2026-09-29 15:24 UTCEPSS rescore
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  12. 2026-09-28 21:24 UTCGHSA enrichment
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  15. 2026-09-27 20:40 UTCGHSA enrichment
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  18. 2026-09-26 21:38 UTCGHSA enrichment
  19. 2026-09-26 15:59 UTCEPSS rescore
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  21. 2026-09-25 16:03 UTCEG score recompute
  22. 2026-09-25 16:03 UTCGHSA enrichment
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  24. 2026-09-24 16:58 UTCGHSA enrichment
  25. 2026-09-24 14:04 UTCEPSS rescore
  26. 2026-09-23 17:55 UTCEG score recompute
  27. 2026-09-23 17:55 UTCGHSA enrichment
  28. 2026-09-23 17:54 UTCEPSS rescore
  29. 2026-09-22 18:52 UTCEG score recompute
  30. 2026-09-22 18:52 UTCGHSA enrichment
  31. 2026-09-22 16:01 UTCEPSS rescore
  32. 2026-09-21 21:09 UTCEPSS rescore
  33. 2026-09-21 18:41 UTCEG score recompute
  34. 2026-09-21 18:41 UTCGHSA enrichment
  35. 2026-09-20 20:16 UTCEPSS rescore
  36. 2026-09-20 19:38 UTCGHSA enrichment
  37. 2026-09-19 20:35 UTCEG score recompute
  38. 2026-09-19 20:35 UTCGHSA enrichment
  39. 2026-09-18 21:32 UTCEG score recompute
  40. 2026-09-18 21:32 UTCGHSA enrichment
  41. 2026-09-18 19:28 UTCEPSS rescore
  42. 2026-09-17 21:01 UTCEG score recompute
  43. 2026-09-17 21:01 UTCGHSA enrichment
  44. 2026-09-16 19:14 UTCEG score recompute
  45. 2026-09-16 19:14 UTCGHSA enrichment
  46. 2026-09-16 14:08 UTCEPSS rescore
  47. 2026-09-16 05:15 UTCEPSS rescore
  48. 2026-09-15 19:45 UTCEG score recompute
  49. 2026-09-15 19:45 UTCGHSA enrichment
  50. 2026-09-15 03:12 UTCEPSS rescore
  51. 2026-09-15 03:12 UTCEPSS rescore
  52. 2026-09-14 20:32 UTCGHSA enrichment
  53. 2026-09-13 21:29 UTCEG score recompute
  54. 2026-09-13 21:29 UTCGHSA enrichment
  55. 2026-09-12 22:26 UTCEG score recompute
  56. 2026-09-12 22:26 UTCGHSA enrichment
  57. 2026-09-12 15:02 UTCEPSS rescore
  58. 2026-09-11 23:22 UTCEG score recompute
  59. 2026-09-11 23:22 UTCGHSA enrichment
  60. 2026-09-11 14:53 UTCEPSS rescore
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  62. 2026-09-10 23:16 UTCGHSA enrichment
  63. 2026-09-10 09:35 UTCEPSS rescore
  64. 2026-09-10 00:12 UTCGHSA enrichment
  65. 2026-09-09 00:56 UTCEG score recompute
  66. 2026-09-09 00:56 UTCGHSA enrichment
  67. 2026-09-08 22:01 UTCEPSS rescore
  68. 2026-09-07 15:14 UTCEG score recompute
  69. 2026-09-07 15:14 UTCGHSA enrichment
  70. 2026-09-06 13:48 UTCEPSS rescore
  71. 2026-09-06 13:12 UTCEG score recompute
  72. 2026-09-06 13:12 UTCGHSA enrichment
  73. 2026-09-05 14:09 UTCGHSA enrichment
  74. 2026-09-04 15:03 UTCEG score recompute
  75. 2026-09-04 15:03 UTCGHSA enrichment

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Frequently asked(5)

What is CVE-2026-77680?
CVE-2026-77680 is a medium vulnerability published on August 25, 2026. 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…
When was CVE-2026-77680 disclosed?
CVE-2026-77680 was first published on August 25, 2026, with the most recent update on August 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-77680 actively exploited?
CVE-2026-77680 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (25th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-77680?
CVE-2026-77680 has a CVSS base score of 5.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-77680?
A fix for CVE-2026-77680 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-77680 are linked in the Vendor Advisories panel on this page.

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