> CVE-2026-5928

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PUBLISHED
2026-04-20 21:16
MODIFIED
2026-04-20 21:16
EPSS (Prob. Exploit)
0.49%
Top 58.5%
DATA SOURCES:
NVD 🔗 2026-04-20 RED HAT 🔗 2026-04-26 CWE MITRE 🔗 2026-11-01 FIRST EPSS 🔗 2026-10-25 OSV 🔗 2026-07-26 MSRC 🔗 2026-11-02

> DESCRIPTION

Calling the ungetwc function on a FILE stream with wide characters encoded in a character set that has overlaps between its single byte and multi-byte character encodings, in the GNU C Library version 2.43 or earlier, may result in an attempt to read bytes before an allocated buffer, potentially resulting in unintentional disclosure of neighboring data in the heap, or a program crash. A bug in the wide character pushback implementation (_IO_wdefault_pbackfail in libio/wgenops.c) causes ungetwc() to operate on the regular character buffer (fp->_IO_read_ptr) instead of the actual wide-stream read pointer (fp->_wide_data->_IO_read_ptr). The program crash may happen in cases where fp->_IO_read_ptr is not initialized and hence points to NULL. The buffer under-read requires a special situation where the input character encoding is such that there are overlaps between single byte representations and multibyte representations in that encoding, resulting in spurious matches. The spurious match case is not possible in the standard Unicode character sets.

> AFFECTED_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> WEAKNESSES

CWE-127

> CWE DETAILED DESCRIPTIONS

CWE-127: Buffer Under-read - The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations prior to the targeted buffer.

> RED HAT SECURITY ADVISORIES

Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
An update for Red Hat Hardened Images RPMs is now available.
Red Hat Security Advisory: glibc security update
An update for glibc is now available for Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVS...
Red Hat Security Advisory: glibc security update
An update for glibc is now available for Red Hat Enterprise Linux 10. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CV...
Red Hat Security Advisory: glibc security update
An update for glibc is now available for Red Hat Enterprise Linux 9. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVS...
Red Hat Security Advisory: Red Hat Update Infrastructure 5.2 security update
The latest release of Red Hat Update Infrastructure. For more details, see the product documentation.
Red Hat Security Advisory: Red Hat OpenShift distributed tracing platform (Tempo) 3.10.2 release
Red Hat OpenShift distributed tracing platform (Tempo) 3.10.2 has been released
Red Hat Security Advisory: A Subscription Management tool for finding and reporting Red Hat product usage
A Subscription Management tool for finding and reporting Red Hat product usage
Red Hat Security Advisory: Red Hat build of OpenTelemetry 3.10.1 release
Red Hat build of OpenTelemetry 3.10.1 has been released
Red Hat Security Advisory: Insights proxy Container Image
Initial GA Release of Red Hat Insights proxy
Red Hat Security Advisory: Red Hat Update Infrastructure 5.3 Technology Preview security update
A new set of Red Hat Update Infrastructure container images is now available as a Technology Preview in the Red Hat container registry.
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.20.1
cert-manager Operator for Red Hat OpenShift 1.20.1
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.20.1
cert-manager Operator for Red Hat OpenShift 1.20.1
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.20.1
cert-manager Operator for Red Hat OpenShift 1.20.1
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.20.1
cert-manager Operator for Red Hat OpenShift 1.20.1
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.20.1
cert-manager Operator for Red Hat OpenShift 1.20.1
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.20.1
cert-manager Operator for Red Hat OpenShift 1.20.1
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.20.1
cert-manager Operator for Red Hat OpenShift 1.20.1
Red Hat Security Advisory: Cost Management Metrics Operator Update
Cost Management Metrics Operator version 4.5.0 release.
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2
cert-manager Operator for Red Hat OpenShift 1.18.2
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2
cert-manager Operator for Red Hat OpenShift 1.18.2
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2
cert-manager Operator for Red Hat OpenShift 1.18.2
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.17.1
cert-manager Operator for Red Hat OpenShift 1.17.1
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.17.2
cert-manager Operator for Red Hat OpenShift 1.17.2
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.17.2
cert-manager Operator for Red Hat OpenShift 1.17.2
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.17.2
cert-manager Operator for Red Hat OpenShift 1.17.2
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2
cert-manager Operator for Red Hat OpenShift 1.18.2

> RED HAT SEVERITY ASSESSMENT

THREAT SEVERITY
Moderate

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

Potential buffer under-read in ungetwc

AFFECTED PACKAGES:
Unknown / Unknown
1242 versions affected

> HISTORIQUE DES MODIFICATIONS

Première apparition
20/04/2026 21:16
Source: NVD
📊 ENRICHISSEMENT 01/05/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-127: Buffer Under-read - The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations prior to the targeted buffer.
📊 ENRICHISSEMENT 26/04/2026 05:02
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
N/A
Nouvelle valeur:
{ "threat_severity": "Moderate", "severity_scale": null }
📊 ENRICHISSEMENT 26/04/2026 05:02
REDHAT
Champ modifié: Red Hat
Ancienne valeur:
Non
Nouvelle valeur:
Oui
Total des modifications: 3 Dernière mise à jour: 6 months ago

> REFERENCES

https://sourceware.org/bugzilla/show_bug.cgi?id=33998
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