Integer Overflow or Wraparound Affecting php package, versions [,8.2.34)[8.3.0RC1,8.3.35)[8.4.0RC1,8.4.26)[8.5.0RC1,8.5.11)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-UNMANAGED-PHP-20158683
- published27 Sept 2026
- disclosed25 Sept 2026
- creditarnoldasr, Oblivionsage, OSTIF-Derek
Introduced: 25 Sep 2026
NewCVE-2026-6103 (opens in a new tab)How to fix?
Upgrade php to version 8.2.34, 8.3.35, 8.4.26, 8.5.11 or higher.
Overview
Affected versions of this package are vulnerable to Integer Overflow or Wraparound in the phar_tar_number() function in ext/phar/tar.c, which accumulates the 11 digit octal size field of a TAR header into a 32-bit unsigned integer with no bound, so a value such as 40000000000 representing 0x100000000 wraps to 0. An attacker can have entries extracted that are not present in the archive as parsed correctly, by setting an entry's size field to a wrapping value so the parser skips the wrong number of data blocks and reads that entry's body content as the next TAR header. This requires the application to open an attacker-supplied archive with PharData or the phar:// stream wrapper, which puts package managers in scope, since Composer's TarDownloader opens downloaded archives with PharData and calls extractTo() into the vendor directory.