CVE-2026-29035

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreHIGH confidence

Score 6.5 from GitHub Security Advisory (severity: HIGH) published 2026-08-11. the CNA's CVSS baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:vulncheck, epss, ghsa
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%CVSS: 6.5Exploit: None knownExposed: 0

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

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
6.5(high)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

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%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
39%
KEV
Not listed

Published

August 11, 2026

Last Modified

August 14, 2026

Advisory Details (2)

Auto-updated Aug 11, 2026
No patch confirmed 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.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 22× in last 7d / 32× 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.

  1. 2026-08-21 01:12 UTCEG score recompute
  2. 2026-08-21 01:12 UTCGHSA enrichment
  3. 2026-08-20 22:55 UTCEPSS rescore
  4. 2026-08-20 22:55 UTCEPSS rescore
  5. 2026-08-19 23:52 UTCEG score recompute
  6. 2026-08-19 23:52 UTCGHSA enrichment
  7. 2026-08-19 17:03 UTCEPSS rescore
  8. 2026-08-18 22:31 UTCEG score recompute
  9. 2026-08-18 22:31 UTCGHSA enrichment
  10. 2026-08-18 13:48 UTCEPSS rescore
  11. 2026-08-17 21:10 UTCEG score recompute
  12. 2026-08-17 21:10 UTCGHSA enrichment
  13. 2026-08-17 13:47 UTCEPSS rescore
  14. 2026-08-16 19:50 UTCEG score recompute
  15. 2026-08-16 19:50 UTCGHSA enrichment
  16. 2026-08-16 14:56 UTCEPSS rescore
  17. 2026-08-16 02:14 UTCEPSS rescore
  18. 2026-08-15 18:30 UTCEG score recompute
  19. 2026-08-15 18:30 UTCGHSA enrichment
  20. 2026-08-15 01:30 UTCEPSS rescore
  21. 2026-08-14 17:09 UTCEG score recompute
  22. 2026-08-14 17:09 UTCGHSA enrichment
  23. 2026-08-13 22:00 UTCEPSS rescore
  24. 2026-08-13 18:56 UTCGHSA enrichment
  25. 2026-08-12 17:36 UTCEG score recompute
Show 7 more
  1. 2026-08-12 17:35 UTCGHSA enrichment
  2. 2026-08-12 17:07 UTCEG score recompute
  3. 2026-08-12 17:07 UTCGHSA enrichment
  4. 2026-08-12 13:50 UTCEPSS rescore
  5. 2026-08-11 21:18 UTCEG score recompute
  6. 2026-08-11 20:30 UTCEG score recompute
  7. 2026-08-11 20:30 UTCMITRE cvelistV5first tracked

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 in the National Vulnerability Database on August 11, 2026, with the most recent update on August 14, 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% probability of exploitation in the next 30 days, which ranks it in the top 61.3% of all scored CVEs.
What is the CVSS score of CVE-2026-29035?
CVE-2026-29035 has a CVSS v4.0 base score of 6.5 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-29035?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-29035, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-29035

Explore →

Is Your Infrastructure Affected by CVE-2026-29035?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs