CVE-2019-17263 — In libyal libfwsi before 20191006, libfwsi_extension_block_copy_from_byte_stream

In libyal libfwsi before 20191006, libfwsi_extension_block_copy_from_byte_stream in libfwsi_extension_block.c has a heap-based buffer over-read because rejection of an unsupported size only considers values less than 6, even though values of 6 and 7 are also unsupported. NOTE: th

01What is this vulnerability?

In libyal libfwsi before 20191006, libfwsi_extension_block_copy_from_byte_stream in libfwsi_extension_block.c has a heap-based buffer over-read because rejection of an unsupported size only considers values less than 6, even though values of 6 and 7 are also unsupported. NOTE: the vendor has disputed this as described in the GitHub issue

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2019-10-06T21:16:50.000Z
• Last modified: 2024-08-05T01:33:17.368Z

09References

• github.com — https://github.com/libyal/libfwsi/issues/13
• github.com — https://github.com/libyal/libfwsi/compare/20181227...20191006
• packetstormsecurity.com — http://packetstormsecurity.com/files/154774/libyal-libfwsi-Buffer-Overread.html