CVE-2021-43539: debian debian_linux Use After Free

CVSS: 8.8v3.1HighModified

AliasesUBUNTU-CVE-2021-43539DEBIAN-CVE-2021-43539

Published 08-12-2021Last modified 04-08-2024

Vulnerability summary

CVE-2021-43539 is a high (CVSS 8.8) Use After Free vulnerability in debian debian_linux. EPSS estimates a 1.73% chance of exploitation in the next 30 days, higher than 77.3% of scored vulnerabilities.

Overall risk

36/100

0100

Medium · default modelHow is this calculated?

CVSS score

8.8/10

010

High · v3.1 (NVD)

EPSS score

1.73%

0%100%

Low · +0.12 pp in 30 days

KEVNot listedIn no KEV catalog

RansomwareNone recordedNo known use recorded

Public exploits0No public exploits recorded

Timeline

08-12-2021
PublishedVulnerability first disclosed.
04-08-2024
Last modifiedVulnerability information updated.

Description

Failure to correctly record the location of live pointers across wasm instance calls resulted in a GC occurring within the call not tracing those live pointers. This could have led to a use-after-free causing a potentially exploitable crash. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.

CVSS metrics

4 scores · 3 sources · 2 versions

v3.18.8v2.06.8

EPSS trend

Probability

1.73%

Chance of exploitation in the next 30 days

Percentile

77%

Versus all other CVEs

30-day change

+0.12 pp

From 1.61% on 19-09-2026

19-09-202619-10-2026

EPSS score

1.73%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

CWE-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Affected systems

Ubuntu6 products

firefox< 95.0+build1-0ubuntu0.18.04.1 | < 95.0+build1-0ubuntu0.20.04.1 | < 95.0+build1-0ubuntu1
mozjs38All versions (No fix recorded)
mozjs52All versions (No fix recorded)
mozjs68All versions (No fix recorded)
mozjs78All versions (No fix recorded)

Show all 6

Debian3 products

firefox-esr< 91.4.0esr-1
thunderbird< 1:91.4.0-1
debian_linuxEOL9.0 | 10.0 | 11.0

Mozilla3 products

firefox≥ unspecified, < 95 | < 95.0
firefox_esr≥ unspecified, < 91.4.0 | < 91.4.0
thunderbird≥ unspecified, < 91.4.0 | < 91.4.0

3 vendors · 12 products

References

19 links

www.mozilla.org/security/advisories/mfsa2021-53/X Refsource MISCVendor Advisory
www.mozilla.org/security/advisories/mfsa2021-54/X Refsource MISCVendor Advisory
www.mozilla.org/security/advisories/mfsa2021-52/X Refsource MISCVendor Advisory
bugzilla.mozilla.org/show_bug.cgi?id=1739683X Refsource MISCIssue TrackingPermissions RequiredVendor Advisory
www.debian.org/security/2021/dsa-5026Vendor AdvisoryX Refsource DEBIANThird Party Advisory
lists.debian.org/debian-lts-announce/2021/12/msg00030.htmlMailing ListX Refsource MLISTThird Party Advisory
www.debian.org/security/2022/dsa-5034Vendor AdvisoryX Refsource DEBIANThird Party Advisory
lists.debian.org/debian-lts-announce/2022/01/msg00001.htmlMailing ListX Refsource MLISTThird Party Advisory
security.gentoo.org/glsa/202202-03Vendor AdvisoryX Refsource GENTOOThird Party Advisory
security.gentoo.org/glsa/202208-14Vendor AdvisoryX Refsource GENTOOThird Party Advisory

Show all 19 references

Vulnerability summary

Advisory lineage

Timeline

Description

CVSS metrics

EPSS trend

Known exploited

Public exploits

Weaknesses

Affected systems

References

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