# CVE-2026-101014: OpenDMARC off-by-one buffer overflow in opendmarc_util_cleanup

Source: https://junglewise.ai/threats/cve-2026-101014-a-vulnerability-was-detected-in-trusted-domain-project-opendmarc  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-28. Updated: 2026-09-28  
License: CC BY 4.0 with a link back

CVE-2026-101014 · Severity: high · CVSS 7.3 · Published 2026-09-28

OpenDMARC is a library that validates DMARC email authentication records. An off-by-one error in the buffer length check allows an attacker to write one byte past the intended buffer boundary, potentially causing a crash or enabling code execution through memory corruption. The vulnerability affects OpenDMARC up to version 1.4.2 and can be exploited remotely without authentication.

Technologies: [Trusted Domain Project OpenDMARC](https://junglewise.ai/threats/technologies/opendmarc). Vendors: [Trusted Domain Project](https://junglewise.ai/threats/vendors/trusted-domain-project).

## Quick answers

**Is CVE-2026-101014 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-101014 being exploited in the wild.

**How severe is CVE-2026-101014?** High severity, with a CVSS score of 7.3, published 28 September 2026.

**Which products and versions are affected?** Trusted Domain Project OpenDMARC up to 1.4.2.

**Is there a fix for CVE-2026-101014?** A patch was published on 2021-09-16: Patch commit b3b1da9 merged to fix off-by-one comparison Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-101014 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-101014?** Check whether you run Trusted Domain Project OpenDMARC at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is an off-by-one error in the opendmarc_util_cleanup function in libopendmarc/opendmarc_util.c, where the buffer boundary check uses > instead of >=, allowing a string exactly equal to buflen to bypass validation and write past the buffer. This is a classic heap or stack buffer overflow with remote network attack vector if the library processes untrusted DMARC record data. A patch fixing the comparison operator from > to >= was merged in commit b3b1da9.

## Affected products

- Trusted Domain Project OpenDMARC up to 1.4.2

## Timeline

- 2026-09-28: disclosed: CVE-2026-101014 published
- 2021-09-16: patched: Patch commit b3b1da9 merged to fix off-by-one comparison

## References

- [https://github.com/trusteddomainproject/OpenDMARC/commit/b3b1da9264bc80324094a27c71e7369bdedc62ae](https://github.com/trusteddomainproject/OpenDMARC/commit/b3b1da9264bc80324094a27c71e7369bdedc62ae)
- [https://github.com/trusteddomainproject/OpenDMARC/pull/188](https://github.com/trusteddomainproject/OpenDMARC/pull/188)

## Related threats

- [OpenDMARC improper authentication in SPF macro handler](https://junglewise.ai/threats/cve-2026-101281-a-flaw-has-been-found-in-trusted-domain-project-opendmarc-up-to)
- [Trusted Domain Project OpenDMARC authentication bypass in Multi-Record Set Handler](https://junglewise.ai/threats/cve-2026-101280-a-vulnerability-was-detected-in-trusted-domain-project-opendmarc)
- [Trusted Domain Project OpenDMARC integer overflow in DMARC parser](https://junglewise.ai/threats/cve-2026-101279-a-security-vulnerability-has-been-detected-in-trusted-domain)
- [Trusted Domain Project OpenDMARC origin validation error in PSL Wildcard Handler](https://junglewise.ai/threats/cve-2026-101278-a-weakness-has-been-identified-in-trusted-domain-project)
- [Trusted Domain Project OpenDMARC exception handling in strcasecmp](https://junglewise.ai/threats/cve-2026-101017-a-vulnerability-was-found-in-trusted-domain-project-opendmarc-up)