CVE-2026-20347

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-08-07. a secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: None knownExposed: 0

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

A vulnerability in the Mach-O file format parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition or possibly other expanded impacts as a result of memory corruption on an affected device. This vulnerability is due to improper boundary checks for content in Mach-O files during scanning, which may result in an out-of-bounds buffer read. An attacker could exploit this vulnerability by submitting a crafted Mach-O file to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to cause the ClamAV scanning process to terminate, resulting in a DoS condition on the affected software.

CVSS v3
7.5
EG Score
7.5(high)
EG Risk
49(Track)
EG Risk 49/100SSVC: 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
Severity75% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
26%
KEV
Not listed

Published

August 7, 2026

Last Modified

August 11, 2026

Advisory Details (1)

Auto-updated Aug 7, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic🟡 PoC Available

ClamAV Vulnerabilities Affecting Cisco Products: August 2026

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-clamav-WuuvVd26

Vendor Advisories for CVE-2026-20347(3)

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

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
clamav0.103.10+dfsg-0+deb11u1 ... 1.4.5+dfsg-3 (57 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
clamav1.0.1+dfsg-2 ... 1.4.5+dfsg-3 (36 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
clamav1.4.3+dfsg-1 ... 1.4.5+dfsg-3 (7 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
clamav1.4.3+dfsg-1 ... 1.4.5+dfsg-3 (7 versions)——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 28× in last 7d / 58× 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. 2026-08-20 22:55 UTCEPSS rescore
  2. 2026-08-20 22:38 UTCGHSA enrichment
  3. 2026-08-20 10:26 UTCGHSA enrichment
  4. 2026-08-19 22:15 UTCEG score recompute
  5. 2026-08-19 22:15 UTCGHSA enrichment
  6. 2026-08-19 17:03 UTCEPSS rescore
  7. 2026-08-19 10:03 UTCGHSA enrichment
  8. 2026-08-18 21:48 UTCEG score recompute
  9. 2026-08-18 21:48 UTCGHSA enrichment
  10. 2026-08-18 13:48 UTCEPSS rescore
  11. 2026-08-18 09:37 UTCGHSA enrichment
  12. 2026-08-17 21:25 UTCEG score recompute
  13. 2026-08-17 21:25 UTCGHSA enrichment
  14. 2026-08-17 13:47 UTCEPSS rescore
  15. 2026-08-17 09:13 UTCGHSA enrichment
  16. 2026-08-16 21:01 UTCEG score recompute
  17. 2026-08-16 21:01 UTCGHSA enrichment
  18. 2026-08-16 14:56 UTCEPSS rescore
  19. 2026-08-16 08:49 UTCEG score recompute
  20. 2026-08-16 08:49 UTCGHSA enrichment
  21. 2026-08-16 02:14 UTCEPSS rescore
  22. 2026-08-15 20:38 UTCGHSA enrichment
  23. 2026-08-15 08:26 UTCEG score recompute
  24. 2026-08-15 08:26 UTCGHSA enrichment
  25. 2026-08-15 01:30 UTCEPSS rescore
Show 33 more
  1. 2026-08-14 20:14 UTCGHSA enrichment
  2. 2026-08-14 08:03 UTCEG score recompute
  3. 2026-08-14 08:03 UTCGHSA enrichment
  4. 2026-08-13 22:00 UTCEPSS rescore
  5. 2026-08-13 19:51 UTCGHSA enrichment
  6. 2026-08-13 07:40 UTCGHSA enrichment
  7. 2026-08-12 19:28 UTCEG score recompute
  8. 2026-08-12 19:28 UTCGHSA enrichment
  9. 2026-08-12 13:50 UTCEPSS rescore
  10. 2026-08-12 07:16 UTCGHSA enrichment
  11. 2026-08-11 19:04 UTCEG score recompute
  12. 2026-08-11 19:04 UTCGHSA enrichment
  13. 2026-08-11 13:42 UTCEPSS rescore
  14. 2026-08-11 11:55 UTCEG score recompute
  15. 2026-08-11 11:55 UTCGHSA enrichment
  16. 2026-08-11 00:00 UTCEPSS rescore
  17. 2026-08-10 23:44 UTCGHSA enrichment
  18. 2026-08-10 11:32 UTCGHSA enrichment
  19. 2026-08-09 23:20 UTCEG score recompute
  20. 2026-08-09 23:20 UTCGHSA enrichment
  21. 2026-08-09 13:46 UTCEPSS rescore
  22. 2026-08-09 11:09 UTCGHSA enrichment
  23. 2026-08-08 22:57 UTCEG score recompute
  24. 2026-08-08 22:57 UTCGHSA enrichment
  25. 2026-08-08 16:37 UTCEPSS rescore
  26. 2026-08-08 10:45 UTCGHSA enrichment
  27. 2026-08-07 22:33 UTCEG score recompute
  28. 2026-08-07 22:33 UTCGHSA enrichment
  29. 2026-08-07 21:22 UTCEG score recompute
  30. 2026-08-07 21:22 UTCGHSA enrichment
  31. 2026-08-07 17:25 UTCEG score recompute
  32. 2026-08-07 16:47 UTCEG score recompute
  33. 2026-08-07 16:47 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-20347?
CVE-2026-20347 is a high vulnerability published on August 7, 2026. A vulnerability in the Mach-O file format parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition or possibly other expanded impacts as a result of memory corruption on an affected device. This vulnerability is due to improper boundary checks for content in…
When was CVE-2026-20347 disclosed?
CVE-2026-20347 was first published in the National Vulnerability Database on August 7, 2026, with the most recent update on August 11, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-20347 actively exploited?
CVE-2026-20347 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 74.2% of all scored CVEs.
What is the CVSS score of CVE-2026-20347?
CVE-2026-20347 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-20347?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-20347, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-20347

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