CVE-2026-29035

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

Score 6.5 from GitHub Security Advisory (severity: HIGH) published 2026-08-11. A secondary CVSS source baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 6.5Exploit: None knownExposed services: Not assessed

No fix is confirmed yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for the fix.

CivetWeb (commit 4a4f0c95) contains a heap and stack buffer overflow vulnerability in the read_websocket() function that allows unauthenticated remote attackers to corrupt memory by sending compressed WebSocket frames when both USE_ZLIB and MG_EXPERIMENTAL_INTERFACES are defined. Attackers can negotiate permessage-deflate during the WebSocket handshake and send a crafted frame with the RSV1 bit set, causing the server to write a 4-byte zlib sync trailer out-of-bounds past the allocated buffer, leading to heap metadata corruption, denial of service, or potential code execution.

CVSS v3
6.5
EG Score
6.5MEDIUMmedium confidence
EG Risk
29
EG Risk 29/100CISA 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
Severity65% × 45%
Exploitation1% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.
EPSS PROB
0.6%
EPSS %ILE
47th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.

Exploitation none (CISA Vulnrichment) · Automatable no (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 11, 2026

Last Modified

September 24, 2026

Advisory Details (2)

Auto-updated Aug 11, 2026
No fix on record yet.
generic

CivetWeb Heap/Stack Buffer Overflow via WebSocket permessage-deflate Decompression | Advisories | VulnCheck

https://www.vulncheck.com/advisories/civetweb-heap-stack-buffer-overflow-via-websocket-permessage-deflate-decompression
generic

GitHub - civetweb/civetweb: Embedded C/C++ web server · GitHub

https://github.com/civetweb/civetweb

Vendor Advisories for CVE-2026-29035(1)

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

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
civetweb1.15+dfsg-4 ... 1.16+dfsg-6 (7 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
civetweb1.16+dfsg-2 ... 1.16+dfsg-6 (6 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
civetweb1.16+dfsg-2, 1.16+dfsg-3, 1.16+dfsg-4, 1.16+dfsg-5, 1.16+dfsg-6
  • every version on: no fix on record
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 11× in last 7d / 63× 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 147 total refreshes for this CVE.

  1. 2026-10-09 20:07 UTCEPSS rescore
  2. 2026-10-08 17:12 UTCEPSS rescore
  3. 2026-10-07 23:47 UTCEPSS rescore
  4. 2026-10-06 17:35 UTCEG score recompute
  5. 2026-10-06 17:35 UTCGHSA enrichment
  6. 2026-10-06 15:17 UTCEPSS rescore
  7. 2026-10-05 17:42 UTCEPSS rescore
  8. 2026-10-04 23:21 UTCEPSS rescore
  9. 2026-10-04 22:34 UTCGHSA enrichment
  10. 2026-10-03 20:27 UTCEG score recompute
  11. 2026-10-03 20:27 UTCGHSA enrichment
  12. 2026-10-03 14:25 UTCEPSS rescore
  13. 2026-10-02 08:25 UTCEG score recompute
  14. 2026-10-02 08:25 UTCGHSA enrichment
  15. 2026-10-01 19:49 UTCEPSS rescore
  16. 2026-09-30 22:00 UTCEG score recompute
  17. 2026-09-30 22:00 UTCGHSA enrichment
  18. 2026-09-30 15:03 UTCEPSS rescore
  19. 2026-09-28 13:51 UTCEPSS rescore
  20. 2026-09-28 11:24 UTCEG score recompute
  21. 2026-09-28 11:24 UTCGHSA enrichment
  22. 2026-09-27 10:00 UTCEG score recompute
  23. 2026-09-27 10:00 UTCGHSA enrichment
  24. 2026-09-26 15:58 UTCEPSS rescore
  25. 2026-09-26 00:26 UTCEPSS rescore
Show 75 more
  1. 2026-09-24 20:35 UTCEG score recompute
  2. 2026-09-24 20:35 UTCGHSA enrichment
  3. 2026-09-24 11:03 UTCEG score recompute
  4. 2026-09-24 11:03 UTCGHSA enrichment
  5. 2026-09-23 09:43 UTCEG score recompute
  6. 2026-09-23 09:43 UTCGHSA enrichment
  7. 2026-09-22 08:22 UTCEG score recompute
  8. 2026-09-22 08:22 UTCGHSA enrichment
  9. 2026-09-21 06:32 UTCEG score recompute
  10. 2026-09-21 06:32 UTCGHSA enrichment
  11. 2026-09-20 20:15 UTCEPSS rescore
  12. 2026-09-20 20:15 UTCEPSS rescore
  13. 2026-09-20 04:29 UTCEG score recompute
  14. 2026-09-20 04:29 UTCGHSA enrichment
  15. 2026-09-19 03:07 UTCEG score recompute
  16. 2026-09-19 03:07 UTCGHSA enrichment
  17. 2026-09-18 19:28 UTCEPSS rescore
  18. 2026-09-18 19:27 UTCEPSS rescore
  19. 2026-09-18 01:46 UTCEG score recompute
  20. 2026-09-18 01:46 UTCGHSA enrichment
  21. 2026-09-17 19:30 UTCEPSS rescore
  22. 2026-09-17 00:26 UTCEG score recompute
  23. 2026-09-17 00:26 UTCGHSA enrichment
  24. 2026-09-16 14:08 UTCEPSS rescore
  25. 2026-09-16 05:15 UTCEPSS rescore
  26. 2026-09-15 13:30 UTCEG score recompute
  27. 2026-09-15 13:30 UTCGHSA enrichment
  28. 2026-09-14 12:09 UTCEG score recompute
  29. 2026-09-14 12:09 UTCGHSA enrichment
  30. 2026-09-13 16:47 UTCEPSS rescore
  31. 2026-09-13 10:48 UTCEG score recompute
  32. 2026-09-13 10:48 UTCGHSA enrichment
  33. 2026-09-12 15:01 UTCEPSS rescore
  34. 2026-09-12 09:27 UTCEG score recompute
  35. 2026-09-12 09:27 UTCGHSA enrichment
  36. 2026-09-11 14:52 UTCEPSS rescore
  37. 2026-09-11 08:03 UTCEG score recompute
  38. 2026-09-11 08:03 UTCGHSA enrichment
  39. 2026-09-10 09:34 UTCEPSS rescore
  40. 2026-09-10 06:42 UTCGHSA enrichment
  41. 2026-09-09 05:22 UTCEG score recompute
  42. 2026-09-09 05:22 UTCGHSA enrichment
  43. 2026-09-08 22:00 UTCEPSS rescore
  44. 2026-09-07 16:47 UTCEG score recompute
  45. 2026-09-07 16:47 UTCGHSA enrichment
  46. 2026-09-07 16:01 UTCEPSS rescore
  47. 2026-09-06 13:47 UTCEPSS rescore
  48. 2026-09-06 13:47 UTCEPSS rescore
  49. 2026-09-06 05:59 UTCEG score recompute
  50. 2026-09-06 05:59 UTCGHSA enrichment
  51. 2026-09-05 04:37 UTCEG score recompute
  52. 2026-09-05 04:37 UTCGHSA enrichment
  53. 2026-09-04 05:06 UTCEPSS rescore
  54. 2026-09-04 03:16 UTCGHSA enrichment
  55. 2026-09-03 01:25 UTCEG score recompute
  56. 2026-09-03 01:25 UTCGHSA enrichment
  57. 2026-09-02 14:11 UTCEPSS rescore
  58. 2026-09-01 23:06 UTCEG score recompute
  59. 2026-09-01 23:06 UTCGHSA enrichment
  60. 2026-09-01 13:53 UTCEPSS rescore
  61. 2026-09-01 04:39 UTCEPSS rescore
  62. 2026-09-01 04:39 UTCEPSS rescore
  63. 2026-08-31 21:45 UTCEG score recompute
  64. 2026-08-31 21:45 UTCGHSA enrichment
  65. 2026-08-30 19:17 UTCEPSS rescore
  66. 2026-08-30 16:36 UTCEG score recompute
  67. 2026-08-30 16:36 UTCGHSA enrichment
  68. 2026-08-30 01:22 UTCEPSS rescore
  69. 2026-08-29 15:16 UTCEG score recompute
  70. 2026-08-29 15:15 UTCGHSA enrichment
  71. 2026-08-28 21:41 UTCEPSS rescore
  72. 2026-08-28 10:41 UTCEG score recompute
  73. 2026-08-28 10:41 UTCGHSA enrichment
  74. 2026-08-27 14:25 UTCEPSS rescore
  75. 2026-08-27 09:18 UTCEG score recompute

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-29035?
CVE-2026-29035 is a medium vulnerability published on August 11, 2026. CivetWeb (commit 4a4f0c95) contains a heap and stack buffer overflow vulnerability in the readwebsocket() function that allows unauthenticated remote attackers to corrupt memory by sending compressed WebSocket frames when both USEZLIB and MGEXPERIMENTALINTERFACES are defined. Attackers can…
When was CVE-2026-29035 disclosed?
CVE-2026-29035 was first published on August 11, 2026, with the most recent update on September 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-29035 actively exploited?
CVE-2026-29035 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (47th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-29035?
CVE-2026-29035 has a CVSS base score of 6.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-29035?
No fix for CVE-2026-29035 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-29035 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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