# CVE-2026-2781: Integer overflow in the Libraries component in NSS > An integer overflow in the NSS libraries allows attackers to potentially execute arbitrary code or cause a denial of service in Firefox and Thunderbird. - **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** A user has to click or open something - **Fix available:** Yes - **Published:** 24 Feb 2026 - **Updated:** 21 Apr 2026 - **Also known as:** BELL-CVE-2026-2781, DEBIAN-CVE-2026-2781, DLA-4508-1, DSA-6149-1, ECHO-c6c4-6d91-e895, GHSA-q6rm-rhj9-jpg5, SUSE-SU-2026:0740-1, SUSE-SU-2026:0813-1, SUSE-SU-2026:0814-1, UBUNTU-CVE-2026-2781, USN-8071-1 ## What is CVE-2026-2781? CVE-2026-2781 is a high-severity vulnerability in Mozilla Firefox, published on 24 Feb 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link. ### Official description 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. Weakness: CWE-190 (Integer Overflow or Wraparound) ## Which versions are affected by CVE-2026-2781? It affects 2 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `mozilla-nss` | SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 3.112.3-150400.3.63.1 | | `mozilla-nss` | SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | All versions | 3.112.3-150400.3.63.1 | | `mozilla-nss` | SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | All versions | 3.112.3-150400.3.63.1 | | `mozilla-nss` | SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS | All versions | 3.112.3-150400.3.63.1 | | `mozilla-nss` | SUSE:Linux Enterprise Micro 5.2 | All versions | 3.112.3-150000.3.135.1 | | `mozilla-nss` | SUSE:Linux Enterprise Micro 5.3 | All versions | 3.112.3-150400.3.63.1 | | `mozilla-nss` | SUSE:Linux Enterprise Micro 5.4 | All versions | 3.112.3-150400.3.63.1 | | `mozilla-nss` | SUSE:Linux Enterprise Micro 5.5 | All versions | 3.112.3-150400.3.63.1 | | `mozilla-nss` | SUSE:Linux Enterprise Module for Basesystem 15 SP7 | All versions | 3.112.3-150400.3.63.1 | | `mozilla-nss` | SUSE:Linux Enterprise Server 12 SP5-LTSS | All versions | 3.112.3-58.136.1 | | `mozilla-nss` | SUSE:Linux Enterprise Server 15 SP4-LTSS | All versions | 3.112.3-150400.3.63.1 | | `mozilla-nss` | SUSE:Linux Enterprise Server 15 SP5-LTSS | All versions | 3.112.3-150400.3.63.1 | | `mozilla-nss` | SUSE:Linux Enterprise Server 15 SP6-LTSS | All versions | 3.112.3-150400.3.63.1 | | `mozilla-nss` | SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5 | All versions | 3.112.3-58.136.1 | | `mozilla-nss` | SUSE:Linux Enterprise Server for SAP Applications 15 SP4 | All versions | 3.112.3-150400.3.63.1 | | `mozilla-nss` | SUSE:Linux Enterprise Server for SAP Applications 15 SP5 | All versions | 3.112.3-150400.3.63.1 | | `mozilla-nss` | SUSE:Linux Enterprise Server for SAP Applications 15 SP6 | All versions | 3.112.3-150400.3.63.1 | | `mozilla-nss` | openSUSE:Leap 15.6 | All versions | 3.112.3-150400.3.63.1 | Products: Mozilla Firefox, Mozilla Thunderbird. ## How do I fix CVE-2026-2781? Upgrade to a fixed version. ## Is CVE-2026-2781 being exploited? There is no known exploitation of CVE-2026-2781 in the wild and no public exploit code. ## Other vulnerabilities in Mozilla Firefox - [CVE-2019-11708](https://insights.sbomify.com/CVE-2019-11708/): Mozilla Firefox and Thunderbird Sandbox Escape (critical 10.0, exploited in the wild) - [CVE-2010-3765](https://insights.sbomify.com/CVE-2010-3765/): Mozilla Multiple Products Remote Code Execution (critical 9.8, exploited in the wild) - [CVE-2022-26486](https://insights.sbomify.com/CVE-2022-26486/): Mozilla Firefox Use-After-Free (critical 9.6, exploited in the wild) - [CVE-2022-26485](https://insights.sbomify.com/CVE-2022-26485/): Mozilla Firefox Use-After-Free (high 8.8, exploited in the wild) - [CVE-2019-11707](https://insights.sbomify.com/CVE-2019-11707/): Mozilla Firefox and Thunderbird Type Confusion (high 8.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-2781 and fix it if it is affected. What it is: CVE-2026-2781 is a high-severity vulnerability in Mozilla Firefox, published on 24 Feb 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link. Exploitation: There is no known exploitation of CVE-2026-2781 in the wild and no public exploit code. Affected product: Mozilla Firefox. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-2781/ (Markdown: https://insights.sbomify.com/CVE-2026-2781/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-2781 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-2781 - OSV: https://osv.dev/vulnerability/CVE-2026-2781 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-2781/ Summaries are generated and may contain mistakes; the official description above is the record.