CVE-2023-3823 | Security issue with external entity loading in XML without enabling it

Exp

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.

Published: 2023-08-11 Last update: 2025-02-13 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-3823 is rated High Exploit Risk (72.8/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.21%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2023-3823

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2023-3823

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.37% 1.21% +0.84%
2 2026-06-14 0.60% 0.37% -0.24%
3 2026-05-07 — 0.60% —

Full EPSS history (17 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-3823

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.6 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 3.9 4.7 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2023-3823

OS Trackers for CVE-2023-3823

vendor priority summary link
debian not yet assigned CVE-2023-3823 not yet assigned priority: Debian including 2 source packages (php7.4, php8.2), 2 status rows across 2 suites (bookworm, bullseye): resolved 2. https://security-tracker.debian.org/tracker/CVE-2023-3823
gentoo high CVE-2023-3823: 1 GLSA(s) (202408-32), 1 atom(s) (dev-lang/php); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2023-3823
redhat medium — https://access.redhat.com/security/cve/CVE-2023-3823
suse high CVE-2023-3823 severity important: SUSE including 342 source package names (apache2-mod_php7-7.4.33-150200.3.60.1, apache2-mod_php7-7.4.33-150400.4.28.1, …), 1349 product×package rows across 33 product lines (Container bci/php, Container bci/php-apache, … (33 product lines)): Fixed 1349. https://www.suse.com/security/cve/CVE-2023-3823/
ubuntu medium CVE-2023-3823 medium priority: Ubuntu including 6 source packages (php5, php7.0, php7.2, php7.4, php8.1, php8.2), 72 status rows across 12 suites (bionic, focal, jammy, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 56, released 6, needed 5, ignored 3, needs-triage 1, not-affected 1. https://ubuntu.com/security/CVE-2023-3823

Affected software / configurations for CVE-2023-3823

Vendor Product Version Raw CPE
php php >= 8.0.0, < 8.0.30 cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
php php >= 8.1.0, < 8.1.22 cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
php php >= 8.2.0, < 8.2.9 cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
fedoraproject fedora 38 cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

References for CVE-2023-3823

cvelogic Threat Intelligence