CVE-2026-102474

Summary

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.

Affected Software

VendorProductVersion RangeStatus

Weaknesses

  • CWE-787: Out-of-bounds Write

Workarounds

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.

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References