CVE Intelligence
High Memory corruption

CVE-2026-20339 — ClamAV PESpin File Format Processing Integer Overflow Vulnerability

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.

Published Aug 7, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: cisco

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • Technical severity (high)+6
  • Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
—
No EPSS score.
Affects
Cisco
Cisco Secure Endpoint
CVSS base
7.5
High · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
Yes
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Cisco Cisco Secure Endpoint).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Cisco Cisco Secure Endpoint version 7.5.15.21611version 8.4.5.30483version 7.5.21.21732version 8.4.4.30467version 8.4.4.30419version 8.4.3version 7.5.20version 8.4.1.30307
and 138 more version 8.4.2.30317version 8.4.1.30298version 7.5.19version 8.4.0version 8.2.4.30130version 8.2.3.30119version 7.5.17.21680version 7.5.1.20813version 8.2.1.21650version 8.2.1.21612version 7.5.13.21598version 7.5.13.21586version 8.1.7.21585version 7.5.11version 7.5.9version 7.5.7version 8.0.1.21164version 8.0.1.21160version 7.5.5version 7.5.3version 7.5.1.20833version 7.0.5version 6.2.19version 7.3.3version 7.2.13version 6.1.5version 6.3.1version 6.2.5version 7.3.5version 6.2.1version 7.2.7version 7.1.1version 6.3.5version 6.2.9version 7.3.1version 6.1.7version 7.2.11version 7.2.3version 7.1.5version 6.3.3version 7.3.9version 6.2.3version 6.1.9version 6.0.9version 7.2.5version 6.0.7version 6.3.7version 1.12.3version 1.8.0version 1.11.1version 1.12.4version 1.10.0version 1.12.0version 1.8.1version 1.10.1version 1.12.1version 1.12.6version 1.14.0version 1.10.2version 1.12.7version 1.12.2version 1.6.0version 1.9.0version 1.11.0version 1.7.0version 1.13.0version 1.8.4version 1.13.1version 1.9.1version 1.12.5version 1.13.2version 8.1.7.21512version 8.1.7version 8.1.5version 8.1.3.21242version 8.1.3version 8.1.5.21322version 8.1.7.21417version 1.14.1version 1.15.1version 1.15.2version 1.15.3version 1.15.4version 1.15.5version 1.15.6version 1.16.0version 1.16.1version 1.16.2version 1.16.3version 1.18.0version 1.18.1version 1.20.0version 1.21.0version 1.21.1version 1.21.2version 1.21.3version 1.22.0version 1.22.1version 1.22.2version 1.22.3version 1.22.4version 1.24.0version 1.24.1version 1.24.2version 1.24.3version 1.24.4version 1.26.0version 1.24.5version 1.26.1version 1.27.0version 1.15.0version 1.17.0version 1.17.1version 1.17.2version 1.19.0version 1.20.1version 1.20.2version 1.20.3version 1.20.4version 1.20.5version 1.20.6version 1.23.0version 1.23.1version 1.20.7version 1.20.8version 1.25.0version 1.25.1version 1.25.2version 1.27.1version 1.27.2version 7.3.13version 7.3.15version 7.4.1version 7.4.1.20425version 7.4.1.20439version 7.4.3version 7.4.3.20679version 7.4.5
Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
7.5 CVSS 3.1 High 3.9 3.6 psirt@cisco.com via NIST National Vulnerability Database
7.5 CVSS 3.1 High — — cisco via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: psirt@cisco.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-190 · Integer Overflow or Wraparound

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · cisco/cisco secure endpoint
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 15, 2026
  • CVSS changed · 7.5
    Oct 15, 2026 · NIST National Vulnerability Database
  • Source status changed · → Awaiting Analysis
    Oct 15, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 15, 2026 · NIST National Vulnerability Database
  • CVE published
    Aug 7, 2026 · cisco

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

1 on the record

Elsewhere on this site

Cisco
every CVE for this vendor
Memory corruption
same class
CWE-190
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-20345 ClamAV GPT File Format Processing Memory Corruption Vulnerability Aug 7, 2026
  • CVE-2026-20348 ClamAV XAR File Format Processing Memory Corruption Vulnerability Aug 7, 2026
  • CVE-2026-20347 ClamAV Mach-O File Format Processing Memory Corruption Vulnerability Aug 7, 2026
  • CVE-2026-20346 ClamAV PDF File Format Processing Memory Corruption Vulnerability Aug 7, 2026
  • CVE-2026-20338 ClamAV ZIP File Format Processing Memory Corruption Vulnerability Aug 7, 2026
  • CVE-2026-20337 ClamAV ZIP File Format Processing Memory Corruption Vulnerability Aug 7, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No FIRST EPSS score.
  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-20339 is "ClamAV PESpin File Format Processing Integer Overflow Vulnerability", rated High. It affects Cisco Secure Endpoint (Cisco); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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