CVE-2019-17543

CVE-2019-17543 is a high-severity vulnerability in Lz4 Project Lz4 with a CVSS 3.x base score of 8.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.

Key facts

• Severity: High (CVSS 3.x base score 8.1)
• CVSS v2: 6.8
• EPSS exploit prediction: 9% (95th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-787
• Affected product: Lz4 Project Lz4
• Published: 2019-10-14
• Last modified: 2026-06-17

Description

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."

Frequently asked questions

What is CVE-2019-17543?

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."

How severe is CVE-2019-17543?

CVE-2019-17543 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2019-17543 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 9% (95th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-17543?

CVE-2019-17543 affects Lz4 Project Lz4. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2019-17543?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2019-17543 published?

CVE-2019-17543 was published on 2019-10-14 and last updated on 2026-06-17.

References

• http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00069.html
• http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00070.html
• https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=15941
• https://github.com/lz4/lz4/compare/v1.9.1...v1.9.2
• https://github.com/lz4/lz4/issues/801
• https://github.com/lz4/lz4/pull/756
• https://github.com/lz4/lz4/pull/760
• https://lists.apache.org/thread.html/25015588b770d67470b7ba7ea49a305d6735dd7f00eabe7d50ec1e17%40%3Cissues.arrow.apache.org%3E
• https://lists.apache.org/thread.html/543302d55e2d2da4311994e9b0debdc676bf3fd05e1a2be3407aa2d6%40%3Cissues.arrow.apache.org%3E
• https://lists.apache.org/thread.html/793012683dc0fa6819b7c2560e6cf990811014c40c7d75412099c357%40%3Cissues.arrow.apache.org%3E
• https://lists.apache.org/thread.html/9ff0606d16be2ab6a81619e1c9e23c3e251756638e36272c8c8b7fa3%40%3Cissues.arrow.apache.org%3E
• https://lists.apache.org/thread.html/f0038c4fab2ee25aee849ebeff6b33b3aa89e07ccfb06b5c87b36316%40%3Cissues.arrow.apache.org%3E
• https://lists.apache.org/thread.html/f506bc371d4a068d5d84d7361293568f61167d3a1c3e91f0def2d7d3%40%3Cdev.arrow.apache.org%3E
• https://lists.apache.org/thread.html/r0fb226357e7988a241b06b93bab065bcea2eb38658b382e485960e26%40%3Cissues.kudu.apache.org%3E
• https://lists.apache.org/thread.html/r4068ba81066792f2b4d208b39c4c4713c5d4c79bd8cb6c1904af5720%40%3Cissues.kudu.apache.org%3E
• https://lists.apache.org/thread.html/r7bc72200f94298bc9a0e35637f388deb53467ca4b2e2ad1ff66d8960%40%3Cissues.kudu.apache.org%3E
• https://security.netapp.com/advisory/ntap-20210723-0001/
• https://www.oracle.com//security-alerts/cpujul2021.html
• https://www.oracle.com/security-alerts/cpuoct2020.html

Affected products (1)

• cpe:2.3:a:lz4_project:lz4:*:*:*:*:*:*:*:*

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