CVE-2026-2781
published 2026-02-24CVE-2026-2781: Integer overflow in the Libraries component in NSS. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, Thunderbird 140.8, and…
PriorityP347critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
EPSS
0.36%
28.3th percentile
Integer overflow in the Libraries component in NSS. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, Thunderbird 140.8, and Firefox ESR 115.35.
Affected
18 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | firefox | < firefox 148.0-1 (sid) | firefox 148.0-1 (sid) |
| debian | firefox-esr | < firefox 148.0-1 (sid) | firefox 148.0-1 (sid) |
| debian | nss | < firefox 148.0-1 (sid) | firefox 148.0-1 (sid) |
| debian | thunderbird | < firefox 148.0-1 (sid) | firefox 148.0-1 (sid) |
| mozilla | firefox | < 140.8.0 | 140.8.0 |
| mozilla | firefox | < 148.0 | 148.0 |
| mozilla | firefox | — | — |
| mozilla | firefox_esr | < Firefox ESR 115.35 | Firefox ESR 115.35 |
| mozilla | nss | >= 0 < 2:3.61-1+deb11u5 | 2:3.61-1+deb11u5 |
| mozilla | nss | >= 0 < 2:3.87.1-1+deb12u2 | 2:3.87.1-1+deb12u2 |
| mozilla | nss | >= 0 < 2:3.110-1+deb13u1 | 2:3.110-1+deb13u1 |
| mozilla | nss | >= 0 < 2:3.121-1 | 2:3.121-1 |
| mozilla | thunderbird | < 140.8.0 | 140.8.0 |
| mozilla | thunderbird | < 148.0 | 148.0 |
| mozilla | thunderbird | >= 0 < 1:140.8.0esr-1~deb11u1 | 1:140.8.0esr-1~deb11u1 |
| mozilla | thunderbird | >= 0 < 1:140.8.0esr-1~deb12u1 | 1:140.8.0esr-1~deb12u1 |
| mozilla | thunderbird | >= 0 < 1:140.8.0esr-1~deb13u1 | 1:140.8.0esr-1~deb13u1 |
| mozilla | thunderbird | >= 0 < 1:140.8.0esr-1 | 1:140.8.0esr-1 |
CVSS provenance
nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
osv9.8CRITICAL
vendor_debian9.8CRITICAL
vendor_redhat9.8CRITICAL
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Ubuntu
NSS vulnerability
vendor_ubuntu·2026-03-05
CVE-2026-2781 NSS vulnerability
Title: NSS vulnerability
Summary: NSS could be made to crash or run programs if it received specially crafted
network traffic.
USN-8071-1 fixed a vulnerability in nss. This update provides the
corresponding fix for Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, Ubuntu 18.04 LTS,
and Ubuntu 20.04 LTS.
Original advisory details:
It was discovered that NSS incorrectly handled memory when performing
certain GHASH operations. A remote attacker could use this issue to cause
NSS to crash, resulting in a denial of service, or possibly execute
arbitrary code.
Instructions: In general, a standard system update will make all the necessary changes.
Ubuntu
NSS vulnerability
vendor_ubuntu·2026-03-04
CVE-2026-2781 NSS vulnerability
Title: NSS vulnerability
Summary: NSS could be made to crash or run programs if it received specially crafted
network traffic.
It was discovered that NSS incorrectly handled memory when performing
certain GHASH operations. A remote attacker could use this issue to cause
NSS to crash, resulting in a denial of service, or possibly execute
arbitrary code.
Instructions: In general, a standard system update will make all the necessary changes.
Red Hat
firefox: thunderbird: Integer overflow in the Libraries component in NSS
vendor_redhat·2026-02-24·CVSS 9.8
CVE-2026-2781 [CRITICAL] firefox: thunderbird: Integer overflow in the Libraries component in NSS
firefox: thunderbird: Integer overflow in the Libraries component in NSS
Integer overflow in the Libraries component in NSS. This vulnerability affects Firefox < 148, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
Integer overflow in the Libraries component in NSS
Statement: Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
Package: rhel10/firefox-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: rhel10/thunderbird-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: firefox (Red Hat Enterprise Linux 6) - Out of support scope
Package: thunderbird (Red Hat Enterprise Linu
Debian
CVE-2026-2781: firefox - Integer overflow in the Libraries component in NSS. This vulnerability affects F...
vendor_debian·2026·CVSS 9.8
CVE-2026-2781 [CRITICAL] CVE-2026-2781: firefox - Integer overflow in the Libraries component in NSS. This vulnerability affects F...
Integer overflow in the Libraries component in NSS. This vulnerability affects Firefox < 148, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.
Scope: local
sid: resolved (fixed in 148.0-1)
Mozilla
Mozilla Foundation Security Advisory 2026-13: CVE-2026-2781
vendor_mozilla·CVSS 9.8
CVE-2026-2781 [CRITICAL] Mozilla Foundation Security Advisory 2026-13: CVE-2026-2781
Mozilla Foundation Security Advisory 2026-13
CVE: CVE-2026-2781
Product: Firefox
Impact: high
Fixed in: Firefox 148
Mozilla
Mozilla Foundation Security Advisory 2026-17: CVE-2026-2781
vendor_mozilla·CVSS 9.8
CVE-2026-2781 [CRITICAL] Mozilla Foundation Security Advisory 2026-17: CVE-2026-2781
Mozilla Foundation Security Advisory 2026-17
CVE: CVE-2026-2781
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.8
Mozilla
Mozilla Foundation Security Advisory 2026-15: CVE-2026-2781
vendor_mozilla·CVSS 9.8
CVE-2026-2781 [CRITICAL] Mozilla Foundation Security Advisory 2026-15: CVE-2026-2781
Mozilla Foundation Security Advisory 2026-15
CVE: CVE-2026-2781
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.8
Mozilla
Mozilla Foundation Security Advisory 2026-16: CVE-2026-2781
vendor_mozilla·CVSS 9.8
CVE-2026-2781 [CRITICAL] Mozilla Foundation Security Advisory 2026-16: CVE-2026-2781
Mozilla Foundation Security Advisory 2026-16
CVE: CVE-2026-2781
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 148
Mozilla
Mozilla Foundation Security Advisory 2026-31: CVE-2026-2781
vendor_mozilla·CVSS 9.8
CVE-2026-2781 [CRITICAL] Mozilla Foundation Security Advisory 2026-31: CVE-2026-2781
Mozilla Foundation Security Advisory 2026-31
CVE: CVE-2026-2781
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 115.35
GHSA
GHSA-q6rm-rhj9-jpg5: Integer overflow in the Libraries component in NSS
ghsa_unreviewed·2026-02-24
CVE-2026-2781 [CRITICAL] CWE-190 GHSA-q6rm-rhj9-jpg5: Integer overflow in the Libraries component in NSS
Integer overflow in the Libraries component in NSS. This vulnerability affects Firefox < 148 and Firefox ESR < 140.8.
OSV
CVE-2026-2781: Integer overflow in the Libraries component in NSS
osv·2026-02-24·CVSS 9.8
CVE-2026-2781 [CRITICAL] CVE-2026-2781: Integer overflow in the Libraries component in NSS
Integer overflow in the Libraries component in NSS. This vulnerability affects Firefox < 148, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.
No detection rules found.
No public exploits indexed.
Wiz
CVE-2026-2781 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz·CVSS 9.8
CVE-2026-2781 [CRITICAL] CVE-2026-2781 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2026-2781 :
NixOS vulnerability analysis and mitigation
Integer overflow in the Libraries component in NSS. This vulnerability affects Firefox < 148, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.
Source : NVD
## 9.8
Score
Published February 24, 2026
Severity CRITICAL
CNA Score 8.8
Affected Technologies
NixOS
Mozilla Firefox
Has Public Exploit No
Has CISA KEV Exploit No
CISA KEV Release Date N/A
CISA KEV Due Date N/A
Exploitation Probability Percentile (EPSS) 15.4
Exploitation Probability (EPSS) 0.1
Affected packages and libraries
libfreebl3
libsoftokn3
Sources
AlmaLinux 8 Severity HIGH Has Fix Added at: Mar 03, 2026
AlmaLinux 9 Severity HIGH Has Fix Added at: Mar 02, 2026
Debian 11, 12, 13, 14 Severity CRITICAL Has Fix Added at: Feb 24, 2
Bugzilla
CVE-2026-2781 firefox: thunderbird: Integer overflow in the Libraries component in NSS
bugzilla·2026-02-24·CVSS 9.8
CVE-2026-2781 [CRITICAL] CVE-2026-2781 firefox: thunderbird: Integer overflow in the Libraries component in NSS
CVE-2026-2781 firefox: thunderbird: Integer overflow in the Libraries component in NSS
Integer overflow in the Libraries component in NSS. This vulnerability affects Firefox < 148 and Firefox ESR < 140.8.
Discussion:
This issue has been addressed in the following products:
Red Hat Enterprise Linux 8
Via RHSA-2026:3338 https://access.redhat.com/errata/RHSA-2026:3338
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 9
Via RHSA-2026:3339 https://access.redhat.com/errata/RHSA-2026:3339
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 10
Via RHSA-2026:3361 https://access.redhat.com/errata/RHSA-2026:3361
---
This issue has been addressed in the following products:
Red Hat Enterprise Linux 8.4 Advanced Missio
https://bugzilla.mozilla.org/show_bug.cgi?id=2009552https://www.mozilla.org/security/advisories/mfsa2026-13/https://www.mozilla.org/security/advisories/mfsa2026-15/https://www.mozilla.org/security/advisories/mfsa2026-16/https://www.mozilla.org/security/advisories/mfsa2026-17/https://www.mozilla.org/security/advisories/mfsa2026-31/https://lists.debian.org/debian-lts-announce/2026/03/msg00012.html
2026-02-24
Published