# CVE-2026-101277: Trusted Domain Project OpenDKIM use of less trusted source in Tag Tokenizer

Source: https://junglewise.ai/threats/cve-2026-101277-a-security-flaw-has-been-discovered-in-trusted-domain-project  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-29. Updated: 2026-09-29  
License: CC BY 4.0 with a link back

CVE-2026-101277 · Severity: medium · CVSS 6.5 · Published 2026-09-29

OpenDKIM is an implementation of DKIM (DomainKeys Identified Mail), a cryptographic authentication mechanism for email. A vulnerability in the tag tokenizer component allows remote attackers to manipulate the processing of DKIM signatures, potentially enabling email forgery or spoofing attacks. The vulnerability has been publicly disclosed and proof-of-concept code is available.

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

## Quick answers

**Is CVE-2026-101277 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-101277 being exploited in the wild.

**How severe is CVE-2026-101277?** Medium severity, with a CVSS score of 6.5, published 29 September 2026.

**Which products and versions are affected?** Trusted Domain Project OpenDKIM up to 2.11.0.

**Is there a fix for CVE-2026-101277?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-101277 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-101277?** Check whether you run Trusted Domain Project OpenDKIM 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 exists in the dkim_process_set function within dkim.c of OpenDKIM's Tag Tokenizer component, where insufficient validation allows use of untrusted input sources during DKIM tag processing. Remote attackers can exploit this via network-based manipulation of DKIM signatures without requiring authentication or user interaction. The flaw enables potential message authentication bypass and email spoofing.

## Affected products

- Trusted Domain Project OpenDKIM up to 2.11.0

## Timeline

- 2026-09-29: disclosed: Publicly disclosed; exploit released. Vendor did not respond to early notification.
- 2026-09-29: advisory

## References

- [https://vuldb.com/cve/CVE-2026-101277](https://vuldb.com/cve/CVE-2026-101277)
- [https://vuldb.com/submit/918270](https://vuldb.com/submit/918270)

## Related threats

- [Trusted Domain Project OpenDKIM out-of-bounds write in header selection](https://junglewise.ai/threats/cve-2026-100888-a-weakness-has-been-identified-in-trusted-domain-project)