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🛡️ CVE-2023-3823 on Ubuntu — php5

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

Description

In PHP versions 8.0.* before 8.0.30, 8.1.* before 8.1.22, and 8.2.* before 8.2.8 various XML functions rely on libxml global state to track configuration variables, like whether external entities are loaded. This state is assumed to be unchanged unless the user explicitly changes it by calling appropriate function. However, since the state is process-global, other modules - such as ImageMagick - may also use this library within the same process, and change that global state for their internal purposes, and leave it in a state where external entities loading is enabled. This can lead to the situation where external XML is parsed with external entities loaded, which can lead to disclosure of any local files accessible to PHP. This vulnerable state may persist in the same process across many requests, until the process is shut down.

Distribution advisory

This page covers CVE-2023-3823 as tracked by Ubuntu, for the package php5. The fix is available in version 7.0.33-0ubuntu0.16.04.16+esm10; 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. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity none, availability none.

CVSS metrics in full

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

  • 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: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: None.
  • Availability impact: None.

Weakness class

UBUNTU-CVE-2023-3823 is classified as CWE-611: XML External Entity Reference (XXE). An XML parser resolves external entities, letting a crafted document read local files or reach internal services.

Affected software

UBUNTU-CVE-2023-3823 is recorded against 5 packages.

  • php5
  • php7.0 (fixed in 7.0.33-0ubuntu0.16.04.16+esm10)
  • php7.2 (fixed in 7.2.24-0ubuntu0.18.04.17+esm4)
  • php7.4 (fixed in 7.4.3-4ubuntu2.20)
  • php8.1 (fixed in 8.1.2-1ubuntu2.14)

Timeline and source

Published on 11 August 2023 and last revised on 22 April 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

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

Other advisories for this package

php5 has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-611: XML External Entity Reference (XXE)) in other software:

CVE-2023-3823 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:N/S:U/C:H/I:N/A:N
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2023-08-11
Updated 2026-08-20
Modified 2026-04-22
Fix URL N/A

Affected Packages

Software From version Fixed in
php5 — —
php7.0 — 7.0.33-0ubuntu0.16.04.16+esm10
php7.2 — 7.2.24-0ubuntu0.18.04.17+esm4
php7.4 — 7.4.3-4ubuntu2.20
php8.1 — 8.1.2-1ubuntu2.14

Site Security Check

Is php5 part of your stack?

UBUNTU-CVE-2023-3823 is rated CVSS 8.6 High. BotEraser scans your installation against known CVE records and tells you whether this vulnerability applies to the versions you actually run.

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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