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🛡️ CVE-2026-7259 on Ubuntu — php8.1

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

In PHP versions 8.2.* before 8.2.31, 8.3.* before 8.3.31, 8.4.* before 8.4.21, and 8.5.* before 8.5.6, a mismatch between encoding lists in Oniguruma and mbfl leads to  a NULL pointer dereference, resulting in a segmentation fault and denial of service. The vulnerability is exploitable when user-controlled input can influence the encoding passed to mb_regex_encoding().

Distribution advisory

This page covers CVE-2026-7259 as tracked by Ubuntu, for the package php8.1. The fix is available in version 8.1.2-1ubuntu2.24; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. A user must be tricked into taking some action. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: Required — someone has to click, open or visit something.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: None.
  • Integrity impact: None.
  • Availability impact: High — total loss, or loss the attacker controls.

Affected software

UBUNTU-CVE-2026-7259 is recorded against 4 packages.

  • php8.1 (fixed in 8.1.2-1ubuntu2.24)
  • php8.3 (fixed in 8.3.6-0ubuntu0.24.04.9)
  • php8.4 (fixed in 8.4.11-1ubuntu1.2)
  • php8.5 (fixed in 8.5.4-0ubuntu1.1)

Timeline and source

Published on 10 May 2026 and last revised on 28 May 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

ubuntu.com (Report)
www.cve.org (Report)
github.com (Report)
ubuntu.com (Advisory)

Other advisories for this package

php8.1 has other advisories on record. If you are patching this one, these are worth checking on the same host:

CVE-2026-7259 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-05-10
Updated 2026-08-20
Modified 2026-05-28
Fix URL N/A

Affected Packages

Software From version Fixed in
php8.1 — 8.1.2-1ubuntu2.24
php8.3 — 8.3.6-0ubuntu0.24.04.9
php8.4 — 8.4.11-1ubuntu1.2
php8.5 — 8.5.4-0ubuntu1.1

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