ext/pcre: preg_replace() use-after-free when __toString() destroys an… - #23221
Open
devnexen wants to merge 1 commit into
Open
ext/pcre: preg_replace() use-after-free when __toString() destroys an…#23221devnexen wants to merge 1 commit into
devnexen wants to merge 1 commit into
Conversation
… array argument. Fix php#23204 Follow-up on phpGH-23207. preg_replace() has a frameless handler, so the pattern, replacement and subject arrays reached _preg_replace_common() with a refcount of one. Stringifying an entry runs __toString(), which freed arData under the iterator or rehashed it in place. Taking a reference on each table for the duration of the read keeps it alive and turns a mutation into a separation.
devnexen
marked this pull request as ready for review
August 11, 2026 21:24
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
1 participant
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
… array argument.
Fix #23204
Follow-up on GH-23207.
preg_replace() has a frameless handler, so the pattern, replacement and subject arrays reached _preg_replace_common() with a refcount of one. Stringifying an entry runs __toString(), which freed arData under the iterator or rehashed it in place. Taking a reference on each table for the duration of the read keeps it alive and turns a mutation into a separation.