CVE-2020-36403
CVE-2020-36403 is a high-severity vulnerability in Htslib with a CVSS 3.x base score of 8.8. 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 8.8)
- CVSS v2: 6.8
- EPSS exploit prediction: 2% (73rd percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-787
- Affected product: Htslib
- Published:
- Last modified:
Description
HTSlib through 1.10.2 allows out-of-bounds write access in vcf_parse_format (called from vcf_parse and vcf_read).
Frequently asked questions
- What is CVE-2020-36403?
- HTSlib through 1.10.2 allows out-of-bounds write access in vcf_parse_format (called from vcf_parse and vcf_read).
- How severe is CVE-2020-36403?
- CVE-2020-36403 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2020-36403 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2020-36403?
- CVE-2020-36403 affects Htslib. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2020-36403?
- 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-2020-36403 published?
- CVE-2020-36403 was published on 2021-07-01 and last updated on 2026-06-17.
References
- https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=24097
- https://github.com/google/oss-fuzz-vulns/blob/main/vulns/htslib/OSV-2020-955.yaml
- https://github.com/samtools/htslib/commit/dcd4b7304941a8832fba2d0fc4c1e716e7a4e72c
- https://github.com/samtools/htslib/pull/1447
Affected products (1)
- cpe:2.3:a:htslib:htslib:*:*:*:*:*:*:*:*
More vulnerabilities in Htslib
- CVE-2018-13845 — Critical (CVSS 9.8): An issue has been found in HTSlib 1.8. It is a buffer over-read in sam_parse1 in sam.c.
- CVE-2017-1000206 — Critical (CVSS 9.8): samtools htslib library version 1.4.0 and earlier is vulnerable to buffer overflow in the CRAM rANS codec resulting in…
- CVE-2026-31967 — Critical (CVSS 9.1): HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA…
- CVE-2026-31966 — Critical (CVSS 9.1): HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA…
- CVE-2026-31962 — High (CVSS 8.8): HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA…
- CVE-2026-31965 — High (CVSS 8.2): HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA…
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