Incomplete fix for CVE-2026-79992 in Emacs and the TRAMP flaw
The oss-sec advisory, posted by Sean Whitton on 11 October, reports that the fix for CVE-2026-79992 in Emacs was incomplete. A new patch from the TRAMP maintainer is due in Emacs 31.2.
Source: Correção incompleta para a CVE-2026-79992 do Emacs (seclists.org). Text prepared with AI from this source.
What happened and what to do
The oss-sec advisory, posted by Sean Whitton on 11 October 2026, reports that the fix for CVE-2026-79992 in Emacs was incomplete. Wonyoung Jung of 78ResearchLab, using the PatchHawk tool, found that the tramp-user-regexp function did not check some additional problematic characters in user names, which kept the exploit possible. The attached patch from TRAMP maintainer Michael Albinus resolves the issue and will be included in Emacs 31.2, a release with no near-term date.
In practice, a company that uses Emacs with TRAMP to edit files on remote servers should first identify where that combination is in use, including developer workstations and pipelines that reach hosts over SSH. Until Emacs 31.2 is available, it is worth applying the maintainer patch to internal builds, validating user names before they reach TRAMP, and monitoring remote access logs for unusual characters. An inventory of versions and a controlled update process shorten the exposure window.
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We can run a diagnosis of TRAMP and Emacs exposure in your environment, propose and implement the patch application and input validation, and set up monitoring of remote access with ongoing operation.
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