01 Record

CVE-2021-43535

A use-after-free could have occured when an HTTP2 session object was released on a different thread, leading to memory corruption and a potentially exploitable crash. This vulnerability affects

UnratedPUBLISHEDCNA: mozilla

CNA base scoreUnratedNo CNA CVSS vector

View raw JSON

02 Description

A use-after-free could have occured when an HTTP2 session object was released on a different thread, leading to memory corruption and a potentially exploitable crash. This vulnerability affects

03 Exploitation and scoring

Exploitation: Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
SSVC decision: Not assessed by CISA
EPSS probability: 1.11% probability of exploitation activity in the next 30 days.
EPSS percentile: Ranks above 63.6% of scored records. A rank, not a probability.
NVD base score: 8.8 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD analysis status: Modified. NVD last modified this record on 2026-06-17.
Red Hat severity: Important. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published

2021-12-08 21:20Z4 YR AGO

Last updated

2024-08-04 03:55Z2 YR AGO

Reserved

2021-11-08

Assigning CNA

mozilla

Record state

PUBLISHED

Severity

Not rated by the issuing CNA

CNA CVSS vector

Not published by the issuing CNA

Weaknesses

CWE-416Use After FreeVariant

Data version

5.1

Document digest

319380f5cc395cd8a3a85ef4e008e81be6fe0fe8341a1a83625ed9f228f611f9

05 Affected products

VendorProductVersionsPlatforms

MozillaFirefox< 93—

MozillaThunderbird< 91.3—

MozillaFirefox ESR< 91.3—

06 References

www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2021-43/x_refsource_MISC
www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2021-49/x_refsource_MISC
www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2021-50/x_refsource_MISC
bugzilla.mozilla.orghttps://bugzilla.mozilla.org/show_bug.cgi?id=1667102x_refsource_MISC
www.debian.orgDSA-5026https://www.debian.org/security/2021/dsa-5026vendor-advisoryx_refsource_DEBIAN
lists.debian.org[debian-lts-announce] 20211229 [SECURITY] [DLA 2863-1] firefox-esr security updatehttps://lists.debian.org/debian-lts-announce/2021/12/msg00030.htmlmailing-listx_refsource_MLIST
www.debian.orgDSA-5034https://www.debian.org/security/2022/dsa-5034vendor-advisoryx_refsource_DEBIAN
lists.debian.org[debian-lts-announce] 20220104 [SECURITY] [DLA 2874-1] thunderbird security updatehttps://lists.debian.org/debian-lts-announce/2022/01/msg00001.htmlmailing-listx_refsource_MLIST

01 Record index

CVE-2021-43535

02 Description

03 Exploitation and scoring

04 Metadata

05 Affected products

06 References

02 Records

CVE-2021-43535

02 Description

03 Exploitation and scoring

04 Metadata

05 Affected products

06 References