How severe is CVE-2021-36976?

CVE-2021-36976 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-36976 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-36976?

CVE-2021-36976 primarily affects Libarchive. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-36976?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-36976 published?

CVE-2021-36976 was published on 2021-07-20 and last updated on 2026-06-17.

CVE-2021-36976

CVE-2021-36976 is a medium-severity vulnerability in Libarchive with a CVSS 3.x base score of 6.5. 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-416.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.3
EPSS exploit prediction: 3% (85th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-416
Affected product: Libarchive
Published: 2021-07-20
Last modified: 2026-06-17

Description

libarchive 3.4.1 through 3.5.1 has a use-after-free in copy_string (called from do_uncompress_block and process_block).

Frequently asked questions

What is CVE-2021-36976?: libarchive 3.4.1 through 3.5.1 has a use-after-free in copy_string (called from do_uncompress_block and process_block).
How severe is CVE-2021-36976?: CVE-2021-36976 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-36976 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-36976?: CVE-2021-36976 primarily affects Libarchive. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-36976?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-36976 published?: CVE-2021-36976 was published on 2021-07-20 and last updated on 2026-06-17.

References

Affected products (8)

cpe:2.3:a:libarchive:libarchive:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
cpe:2.3:o:apple:ipados:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:watchos:*:*:*:*:*:*:*:*
cpe:2.3:a:splunk:universal_forwarder:*:*:*:*:*:*:*:*
cpe:2.3:a:splunk:universal_forwarder:9.1.0:*:*:*:*:*:*:*

More vulnerabilities in Libarchive

CVE-2022-36227 — Critical (CVSS 9.8): In libarchive before 3.6.2, the software does not check for an error after calling calloc function that can return with…
CVE-2024-37407 — Critical (CVSS 9.1): Libarchive before 3.7.4 allows name out-of-bounds access when a ZIP archive has an empty-name file and mac-ext is…
CVE-2020-9308 — High (CVSS 8.8): archive_read_support_format_rar5.c in libarchive before 3.4.2 attempts to unpack a RAR5 file with an invalid or…
CVE-2018-1000878 — High (CVSS 8.8): libarchive version commit 416694915449219d505531b1096384f3237dd6cc onwards (release v3.1.0 onwards) contains a CWE-416:…
CVE-2018-1000877 — High (CVSS 8.8): libarchive version commit 416694915449219d505531b1096384f3237dd6cc onwards (release v3.1.0 onwards) contains a CWE-415:…
CVE-2016-1541 — High (CVSS 8.8): Heap-based buffer overflow in the zip_read_mac_metadata function in archive_read_support_format_zip.c in libarchive…

All CVEs affecting Libarchive →

Other CWE-416 (Use After Free) vulnerabilities

CVE-2026-13782 — Critical (CVSS 10.0): Use after free in Browser in Google Chrome prior to 150.0.7871.47 allowed a remote attacker who had compromised the…
CVE-2026-4725 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 149…
CVE-2026-4688 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox…
CVE-2025-24085 — Critical (CVSS 10.0): A use after free issue was addressed with improved memory management. This issue is fixed in iOS 18.3 and iPadOS 18.3,…
CVE-2024-43102 — Critical (CVSS 10.0): Concurrent removals of certain anonymous shared memory mappings by using the UMTX_SHM_DESTROY sub-request of…
CVE-2021-32495 — Critical (CVSS 10.0): Radare2 has a use-after-free vulnerability in pyc parser's get_none_object function. Attacker can read freed memory…

Browse all CWE-416 (Use After Free) vulnerabilities →