CVE-2019-17543 — LZ4 before 1

LZ4 before 1.9.2 has a heap-based buffer overflow in LZ4_write32 (related to LZ4_compress_destSize), affecting applications that call LZ4_compress_fast with a large input. (This issue can also lead to data corruption.) NOTE: the vendor states "only a few specific / uncommon

01What is this vulnerability?

LZ4 before 1.9.2 has a heap-based buffer overflow in LZ4_write32 (related to LZ4_compress_destSize), affecting applications that call LZ4_compress_fast with a large input. (This issue can also lead to data corruption.) NOTE: the vendor states "only a few specific / uncommon usages of the API are at risk."

02Affected products

No structured affected-product list available — see references below for vendor advisories.

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: 2019-10-14T02:15:10.873
• Last modified: 2026-10-14T07:16:49.003

09References

• lists.opensuse.org — http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00069.html
• lists.opensuse.org — http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00070.html
• bugs.chromium.org — https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=15941
• github.com — https://github.com/lz4/lz4/compare/v1.9.1...v1.9.2
• github.com — https://github.com/lz4/lz4/issues/801
• github.com — https://github.com/lz4/lz4/pull/756
• github.com — https://github.com/lz4/lz4/pull/760
• lists.apache.org — https://lists.apache.org/thread.html/25015588b770d67470b7ba7ea49a305d6735dd7f00e…
• lists.apache.org — https://lists.apache.org/thread.html/543302d55e2d2da4311994e9b0debdc676bf3fd05e1…
• lists.apache.org — https://lists.apache.org/thread.html/793012683dc0fa6819b7c2560e6cf990811014c40c7…