(release/25.1) xkb: fix buffer re-use in _XkbSetCompatMap#2262
Merged
metux merged 1 commit intorelease/25.1from Apr 21, 2026
Merged
Conversation
If the "compat" buffer has previously been truncated, there will be unused space in the buffer. The code uses this space, but does not update the number of valid entries in the buffer. In the best case, this leads to the new compat entries being ignored. In the worst case, if there are any "skipped" compat entries, the number of valid entries will be corrupted, potentially leading to a buffer read overrun when processing a future request. Set the number of used "compat" entries when re-using previously allocated space in the buffer. CVE-2026-33999, ZDI-CAN-28593 This vulnerability was discovered by: Jan-Niklas Sohn working with TrendAI Zero Day Initiative Signed-off-by: Peter Harris <pharris2@rocketsoftware.com> Acked-by: Olivier Fourdan <ofourdan@redhat.com> Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2176>
metux
pushed a commit
that referenced
this pull request
Apr 18, 2026
metux
deleted the
pr/xkb-fix-buffer-re-use-in-xkbsetcompatmap-_2026-04-18_19-44-54
branch
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
If the "compat" buffer has previously been truncated, there will be
unused space in the buffer. The code uses this space, but does not
update the number of valid entries in the buffer.
In the best case, this leads to the new compat entries being ignored. In the
worst case, if there are any "skipped" compat entries, the number of
valid entries will be corrupted, potentially leading to a buffer read
overrun when processing a future request.
Set the number of used "compat" entries when re-using previously
allocated space in the buffer.
CVE-2026-33999, ZDI-CAN-28593
This vulnerability was discovered by:
Jan-Niklas Sohn working with TrendAI Zero Day Initiative
Signed-off-by: Peter Harris pharris2@rocketsoftware.com
Acked-by: Olivier Fourdan ofourdan@redhat.com
Part-of: https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2176