DEBIAN-CVE-2026-5928

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Source
https://security-tracker.debian.org/tracker/CVE-2026-5928
Import Source
https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-5928.json
JSON Data
https://api.osv.dev/v1/vulns/DEBIAN-CVE-2026-5928
Upstream
Published
2026-04-20T21:16:36Z
Modified
2026-09-14T17:03:21Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Summary
[none]
Details

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.

References

Affected packages

Debian:12 / glibc

Package

Name
glibc
Purl
pkg:deb/debian/glibc?arch=source&distro=bookworm

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

2.*
2.36-9
2.36-9+deb12u1
2.36-9+deb12u2
2.36-9+deb12u3
2.36-9+deb12u4
2.36-9+deb12u5
2.36-9+deb12u6
2.36-9+deb12u7
2.36-9+deb12u8
2.36-9+deb12u9
2.36-9+deb12u10
2.36-9+deb12u11
2.36-9+deb12u12
2.36-9+deb12u13
2.36-9+deb12u14
2.36-9+loong64
2.36-10~0
2.37-1
2.37-2
2.37-3
2.37-4
2.37-5
2.37-6
2.37-7
2.37-8
2.37-9
2.37-10
2.37-11
2.37-12
2.37-13
2.37-14
2.37-15~deb13u1
2.37-15
2.37-15.1
2.37-15.1+sh4
2.37-16
2.37-17
2.37-18
2.37-19
2.38-1
2.38-2
2.38-3
2.38-4
2.38-5
2.38-6
2.38-7~0+hurd.1
2.38-7
2.38-8
2.38-9
2.38-10
2.38-11
2.38-12
2.38-12.1
2.38-13
2.38-14
2.38-15~0
2.38-15~1
2.39-1
2.39-2
2.39-3
2.39-3.1
2.39-4
2.39-5
2.39-6
2.39-6+hurd.1
2.39-6+sh4
2.39-7~0
2.39-7
2.39-7+sh4
2.39-8~0
2.40-1
2.40-2
2.40-2+sh4
2.40-3
2.40-3+sh4
2.40-4
2.40-5~hurd.1
2.40-5
2.40-6~1
2.40-6
2.40-7
2.41-1
2.41-2
2.41-3
2.41-4~0
2.41-4
2.41-5~0
2.41-5
2.41-6
2.41-7
2.41-8~0
2.41-8~1
2.41-8
2.41-9~0
2.41-9~1
2.41-9
2.41-10
2.41-11
2.41-12
2.41-13~hurd.0
2.41-13~hurd.1
2.42-1
2.42-2
2.42-3
2.42-4
2.42-5
2.42-6
2.42-7
2.42-8~hurd.1
2.42-8~hurd.2
2.42-8
2.42-9
2.42-10
2.42-11
2.42-12~hurd.1
2.42-12
2.42-13
2.42-14~hurd.1
2.42-14
2.42-15~hurd.1
2.42-15
2.42-16
2.42-17
2.43-1
2.43-2
2.43-3
2.43-3+m68k
2.43-4
2.43-4+m68k
2.43-5
2.44-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-5928.json"

Debian:13 / glibc

Package

Name
glibc
Purl
pkg:deb/debian/glibc?arch=source&distro=trixie

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2.41-12+deb13u4

Affected versions

2.*
2.41-12
2.41-12+deb13u1
2.41-12+deb13u2
2.41-12+deb13u3

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-5928.json"

Debian:14 / glibc

Package

Name
glibc
Purl
pkg:deb/debian/glibc?arch=source&distro=forky

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2.42-17

Affected versions

2.*
2.41-12
2.41-13~hurd.0
2.41-13~hurd.1
2.42-1
2.42-2
2.42-3
2.42-4
2.42-5
2.42-6
2.42-7
2.42-8~hurd.1
2.42-8~hurd.2
2.42-8
2.42-9
2.42-10
2.42-11
2.42-12~hurd.1
2.42-12
2.42-13
2.42-14~hurd.1
2.42-14
2.42-15~hurd.1
2.42-15
2.42-16

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-5928.json"