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Vulnerabilities

Vulnerability · CVE-2026-6103

phar_tar_number() parses the octal size field of a TAR header into a uint32_t with no overflow check.

Published Sep 25, 2026 · catalog updated Oct 23, 2026 · phar_tar_number() parses the octal

Last checked Oct 25, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-6103. EPSS is 0.16%. Act only if a listed version of phar_tar_number() parses the octal is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (phar_tar_number() parses the octal).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Low3.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.16%
Remediation
Version ranges on file
Affected products
cpe php/php

phar_tar_number() parses the octal size field of a TAR header into a uint32_t with no overflow check. The field is 11 octal digits wide and holds values up to 0x1FFFFFFFF, so a size above 0xFFFFFFFF silently wraps. The parser then skips the wrong number of data blocks and interprets attacker-controlled file content as the next TAR header, which lets a crafted archive inject entries that PharData reports and extracts as if they were genuine.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe php/php< 8.2.34
  • cpe php/php< 8.3.35
  • cpe php/php< 8.4.26
  • cpe php/php< 8.5.11

How to fix CVE-2026-6103

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-6103. EPSS is 0.16%. Act only if a listed version of phar_tar_number() parses the octal is installed.

Which versions are affected?

Compare what you have installed with < 8.2.34, < 8.3.35, < 8.4.26, < 8.5.11. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-190: Integer Overflow. EPSS 0.16%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Sep 25, 2026 · NIST NVD

    Detected

    phar_tar_number() parses the octal size field of a TAR header into a uint32_t with no overflow check. The field is 11 octal digits wide and holds values up to 0x1FFFFFFFF, so a size above 0xFFFFFFFF silently wraps. The parser then skips the wrong number of data blocks and interprets attacker-controlled file content as the next TAR header, which lets a crafted archive inject entries that PharData r

  2. Oct 23, 2026 · NIST NVD

    Updated

    phar_tar_number() parses the octal size field of a TAR header into a uint32_t with no overflow check. The field is 11 octal digits wide and holds values up to 0x1FFFFFFFF, so a size above 0xFFFFFFFF silently wraps. The parser then skips the wrong number of data blocks and interprets attacker-controlled file content as the next TAR header, which lets a crafted archive inject entries that PharData r

Sources

  • CVE.orgVulnerability recordCVE-2026-6103

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-6103

    30-day exploitation probability 0.16%

    first.org
  • NIST NVDVulnerability recordCVE-2026-6103

    phar_tar_number() parses the octal size field of a TAR header into a uint32_t with no overflow check. The field is 11 octal digits wide and holds values up to 0x1FFFFFFFF, so a size above 0xFFFFFFFF silently wraps. The parser then skips the wrong number of data blocks and interpr

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 25, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 25, 2026
  • CVE.orgOct 23, 2026
  • NIST NVDOct 23, 2026