CVE-2026-56131Disclosure(libexpat_project / libexpat)

LOWCVSS 4.9 · MEDIUM

Signal is active with 1 mentions in latest observed window

Immediate actions

Patch libexpat_project libexpat systems immediately

Recommended action window: Monitor and triage in normal cycle

NVD description

libexpat before 2.8.2 lacks handler call depth tracking for calls to XML_ResumeParser from within handlers in cases of a policy violation. Thus, a use-after-free can occur (similar to the CVE-2026-50219 situation).

libexpat_project CVEs Back to dashboard

0.5/ 10 priority

Sources & remediation

Patch / fix

https://github.com/libexpat/libexpat/pull/1267

Weakness type (CWE)

CWE-416

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

AVAILABLE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

libexpat

Threat summary

Patch or workaround signal is available
2 mentions across 2 observed days
Momentum state: stable

What's happening

Patch or workaround mentioned in 1 signal
Technical details provided in 2 signals
Disclosure: 1 classified signal
Peaked 1d ago at 1 mentions (2026-06-19); latest day: 1
2 total mentions across 2 days

Affected systems

Vendors

libexpat_project

Products

libexpat

Deep dive

Activity timeline2 mentions / 2d

Signal classification2 categories

Disclosure

150.0%

Patch

150.0%

Referenced assets2 URLs

By indicator

Classification over time

Date	Total	Labels

2026-06-19	1	Disclosure1
2026-06-29	1	Patch1

Full discourse2 posts

connect24h@connect24h126d
Patch
いやー、地味に嫌なんですけど。XMLを「通るだけの部品」と見ている組織ほど、libexpat 2.8.2未満は今日棚卸ししてほしい。CVE-2026-56403〜56407にinteger overflow、CVE-2026-56132にheap-based buffer overflow、CVE-2026-56131/56412にhandler call depth絡みのuse-after-free系が並ぶ。単体アプリ名ではなく、OS・ミドルウェア・組込み製品・社内ツールに静かに入る波及性。SBOM、コンテナ、静的リンク、XMLを受ける入口を見て、2.8.2以上へ更新可否が必要。地味だけど、こういう基盤ライブラリは後回しが一番怖い。 #セキュリティ https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56405
Post summary
The tweet urges organizations to upgrade libexpat to version 2.8.2 or later to mitigate multiple integer overflow, heap‑based buffer overflow, and use‑after‑free vulnerabilities identified by CVE‑2026‑56403‑56407, 56132, 56131, and 56412.
00001240
4.1K followersView on X
Vulmon Vulnerability Feed@VulmonFeeds136d
Disclosure
CVE-2026-56131 Use-After-Free Vulnerability in libexpat Before 2.8.2 via XML_ResumeParser https://vulmon.com/vulnerabilitydetails?qid=CVE-2026-56131
Post summary
CVE-2026-56131 describes a use‑after‑free vulnerability in libexpat v2.8.2 and earlier affecting XML_ResumeParser. No PoC, exploit code, active exploitation, or patch information is provided.
0000047
4.1K followersView on X

CPE platform detail1 entries

Part:

Vendor:

Product:

Version:

Target SW:

Target HW:

1 of 1 entries

Part	Vendor	Product	Version	Target SW	Target HW
App	libexpat_project	libexpat	-	-	-

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