CVE-2026-20339

HIGH 7.5 ALL-YEARS

Published 2026-08-07 · Last modified 2026-08-07 · cisco · NVD: Awaiting Analysis

A vulnerability in the PESpin 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 PESpin files during scanning, which may result in an integer overflow. An attacker could exploit this vulnerability by submitting a crafted file that contains PESpin content 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.

ELEVATED IMPACT

Severe if exploited (CVSS 7.5), but no confirmed exploitation. Patch on a normal cadence.

Exploitation likelihood

0.6%chance of exploitation in 30 days · 46th percentile

○ In CISA KEV○ Catalogued PoC◆ SSVC: exploitation none, automatable yes

Impact if exploited

7.5CVSS 3.1 · HIGH · CNA

ConfidentialityNone
IntegrityNone
AvailabilityHigh

What an attacker needs

✓Access: Reachable over the network — no local access needed
✓Privileges: No account or privileges required
✓User interaction: No user interaction needed
✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

Search for new PoCs

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Tracked sources are checked weekly for the full archive, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Affected

Vendors Cisco

Products Cisco Secure Endpoint

Weakness (CWE)

CWE-190: Integer Overflow or Wraparound

CVSS vector

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

References and research data (JSON)

All CVSS metrics

HIGH 7.5 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
HIGH 7.5 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

Advisories

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-54506 ADVISORYEUVD · EUVD-2026-54506

Technical & other

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-clamav-WuuvVd26CVE record · cisco · Updated 2026-08-07T16:42:33.962Z
NVD · CVE-2026-20339 · Updated 2026-10-23T20:10:00.160

Sources: NVD · CVE.org · All sources and attribution · EPSS