CVE-2026-85234
Tftp: tftp-hpa: denial of service due to out-of-bounds read/write in remap engine
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.
Fixes and workarounds
Workaround
To mitigate this issue, avoid enabling filename remapping with the `m/-map-file` option for the `in.tftpd` service unless strictly necessary. If filename remapping is required, ensure that any inverse (`~`) and abort (`a`) rules in the remap file do not include a non-empty custom error message. Changes to the `in.tftpd` configuration may require restarting the service to take effect.
Source: CNA: redhatAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| Red Hat Enterprise Linux 10 Red Hat tftp
https://access.redhat.com/downloads/content/package-browser/ |
≥ 0:5.2-50.el10_2; < * (unaffected, rpm)
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 8 Red Hat tftp
https://access.redhat.com/downloads/content/package-browser/ |
≥ 0:5.2-28.el8_10; < * (unaffected, rpm)
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 9 Red Hat tftp
https://access.redhat.com/downloads/content/package-browser/ |
≥ 0:5.2-40.el9_8.1; < * (unaffected, rpm)
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 6 Red Hat tftp
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unknown |
CNA: redhat |
| Red Hat Enterprise Linux 7 Red Hat tftp
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Hardened Images Red Hat erlang27
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unaffected |
CNA: redhat |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 7.5 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CNA: redhat |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://access.redhat.com/errata/RHSA-2026:78952CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:80663CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:82280CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2026-85234CNA: redhat · vdb-entry, x_refsource_REDHAT
- https://bugzilla.redhat.com/show_bug.cgi?id=2460997CNA: redhat · issue-tracking, x_refsource_REDHAT
- https://git.kernel.org/pub/scm/network/tftp/tftp-hpa.git/commit/?id=4b493532f5ce052a1c124acd0661233ec7918327CNA: redhat
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