CVE-2026-102474

Dash: dash: heap out-of-bounds write in conv_escape via undersized unicode escape reservation

Published Sep 29, 2026 CVSS 3.1 · 4 Medium EPSS < 1% KEV · Not listed
Description
A flaw was found in dash. The printf builtin reserves four bytes before converting a Unicode \u or \U escape, but the multi-byte token can need five or six bytes. A local user who can supply such an escape to dash printf or echo %b, including through dash -c and a positional argument, can write one or two bytes past that reservation.

Remediation

Vendor Workaround

No practical runtime mitigation is available in the shipped build. Do not pass untrusted data into dash printf/echo %b or into dash -c as a positional argument. The fix is to raise the CHECKSTRSPACE reservation at both printf call sites to 8. The later unaligned-access memcpy change in conv_escape does not enlarge that reservation and does not fix this issue.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Dash
Dash dash
Red Hat
Red Hat enterprise Linux
Redhat enterprise Linux
Vendors & Products Dash
Dash dash
Red Hat
Red Hat enterprise Linux
Redhat enterprise Linux
Type Values Removed Values Added
First Time appeared Redhat rhel Els
CPEs cpe:/o:redhat:enterprise_linux:6 cpe:/o:redhat:rhel_els:6
Vendors & Products Redhat enterprise Linux
Redhat rhel Els
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description A flaw was found in dash. The printf builtin reserves four bytes before converting a Unicode \u or \U escape, but the multi-byte token can need five or six bytes. A local user who can supply such an escape to dash printf or echo %b, including through dash -c and a positional argument, can write one or two bytes past that reservation.
Title Dash: dash: heap out-of-bounds write in conv_escape via undersized unicode escape reservation
First Time appeared Redhat
Redhat enterprise Linux
Weaknesses CWE-787
CPEs cpe:/o:redhat:enterprise_linux:6
Vendors & Products Redhat
Redhat enterprise Linux
References
Metrics threat_severity

None

cvssV3_1

{'score': 4, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'}

threat_severity

Moderate

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Nov 5, 2026, 4:04 PM
Reserved
Sep 29, 2026, 8:38 AM
Status
Awaiting Analysis
Published
Sep 29, 2026, 10:17 AM
Modified
Nov 5, 2026, 5:17 PM
Severity
Moderate
Public date
Sep 29, 2026, 12:00 AM