CVE & CISA-KEV Catalog

CVE-2026-76956

MEDIUM
7.5
CVSS v3
NVD

Description

In libexpat 2.8.2 and 2.8.3 before 2.8.4, misinterpretation of getentropy's return code leads to insufficient entropy, which results in being vulnerable to hash flooding attacks, causing a denial of service via crafted XML content.

How to fix

Remediation Available
expatDebian
Fixed in:2.8.4-1CVE-2026-76956

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityNone
IntegrityNone
AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U

Exploit Intelligence

0.29%probability of exploitation in 30 days
20thpercentile

Low risk: more likely to be exploited than 20% of all known CVEs.

References

Related Vulnerabilities

Other CWE-394 vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2018-20802Medium6.51.5%-Fix
CVE-2019-0066High7.51.4%--
CVE-2019-20924Medium6.51.3%-Fix
CVE-2022-24880Medium5.31.2%-Fix
CVE-2023-48429Low2.70.6%-Fix
CVE-2023-25948High7.50.6%--

Common questions

How do I fix CVE-2026-76956?

Upgrade expat on debian unstable to 2.8.4-1 or later.

Is CVE-2026-76956 being actively exploited?

Not that we know of. CVE-2026-76956 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.29% is the estimated probability that it will be exploited in the next 30 days. That is higher than 20% of all scored CVEs.

How severe is CVE-2026-76956?

CVE-2026-76956 has a CVSS v3 base score of 7.5, rated moderate. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-76956 affect?

Published advisories record a fix for expat (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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CVE-2026-76956 severity badge

Markdown

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-08.