Medium exploit reference

CVE-2026-101279 — Trusted Domain Project OpenDMARC opendmarc_policy.c integer overflow

A security vulnerability has been detected in Trusted Domain Project OpenDMARC up to 1.4.2. This impacts an unknown function of the file libopendmarc/opendmarc_policy.c of the component DMARC Parser. The manipulation of the argument pct leads to integer overflow. Remote exploitation of the attack is possible. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Published Sep 28, 2026 · Updated Oct 16, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: VulDB

Low

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

EPSS 0.3% (30-day exploitation probability)+4
Technical severity (medium)+3
CISA SSVC: exploitation "poc"+5
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

0.32%

ahead of 24% of scored CVEs · Oct 15, 2026

Affects

Trusted Domain Project

OpenDMARC

CVSS base

6.5

Medium · 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

Proof of concept

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.

Identify exposed assets running the affected vendor/product/version combinations (Trusted Domain Project OpenDMARC).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Trusted Domain Project	OpenDMARC	version 1.4.0version 1.4.1version 1.4.2	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

Low

Availability

Low

Every base score collected

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

Score	Version	Severity	Expl.	Impact	Scored by
6.9	CVSS 4.0	Medium	—	—	VulDB via CVE Program (cve.org) e CISA ADP
5.5	CVSS 4.0	Medium	—	—	cna@vuldb.com via NIST National Vulnerability Database
6.5	CVSS 3.1	Medium	3.9	2.5	cna@vuldb.com via NIST National Vulnerability Database
6.5	CVSS 3.1	Medium	—	—	VulDB via CVE Program (cve.org) e CISA ADP
6.5	CVSS 3.0	Medium	—	—	VulDB via CVE Program (cve.org) e CISA ADP
6.4	CVSS 2.0	Medium	10.0	4.9	cna@vuldb.com via NIST National Vulnerability Database
6.4	CVSS 2.0	Medium	—	—	VulDB via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L (score shown at the top: cna@vuldb.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-189

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).

web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

2026
Affected products added · trusted domain project/opendmarc
Oct 16, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 16, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 15, 2026
CVSS changed · 6.5
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Deferred
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Sep 28, 2026 · VulDB

Source activity

Repeated readings are counted rather than listed.

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

References

5 on the record

vuldb.com/cve/CVE-2026-101279
third-party-advisory, NIST National Vulnerability Database
vuldb.com/vuln/411036
vdb-entry, technical-description, NIST National Vulnerability Database
vuldb.com/vuln/411036/cti
signature, permissions-required, NIST National Vulnerability Database
xuyongzhe-vt.github.io/share/dmarc-pct-integer-handling.html
exploit, NIST National Vulnerability Database
vuldb.com/submit/918280
third-party-advisory, NIST National Vulnerability Database

Elsewhere on this site

Trusted Domain Project
every CVE for this vendor

CWE-189
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-101280 Trusted Domain Project OpenDMARC Multi-Record Set opendmarc_policy_query_dmarc authentication spoofing 17d
High CVE-2026-101281 Trusted Domain Project OpenDMARC SPF Macro opendmarc_spf.c opendmarc_sp2_find_mailfrom_domain improper authentication 17d
Medium CVE-2026-101278 Trusted Domain Project OpenDMARC PSL Wildcard opendmarc_tld.c : opendmarc_get_tld origin validation 17d
High CVE-2026-101015 Trusted Domain Project OpenDMARC policy.c improper validation of unsafe equivalence in input 17d
Medium CVE-2026-101016 Trusted Domain Project OpenDMARC opendmarc_policy.c opendmarc_policy_parse_dmarc exceptional condition 17d
Medium CVE-2026-101017 Trusted Domain Project OpenDMARC opendmarc_policy.c strcasecmp exceptional condition 17d

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 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-2026-101279 is "Trusted Domain Project OpenDMARC opendmarc_policy.c integer overflow", rated Medium. It affects OpenDMARC (Trusted Domain Project); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.5 describes technical severity. EPSS 0.32% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

Comments

Moderated technical discussion. Read the community guidelines.

No comments yet.