How severe is CVE-2026-100788?

CVE-2026-100788 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-100788 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-100788?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-100788 published?

CVE-2026-100788 was published on 2026-09-29 and last updated on 2026-10-01.

CVE-2026-100788

CVE-2026-100788 is a critical-severity vulnerability with a CVSS 3.x base score of 9.8. 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-824.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 0% (36th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-824
Published: 2026-09-29
Last modified: 2026-10-01

Description

Invalid pointer in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.

Frequently asked questions

What is CVE-2026-100788?: Invalid pointer in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.
How severe is CVE-2026-100788?: CVE-2026-100788 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-100788 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-100788?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-100788 published?: CVE-2026-100788 was published on 2026-09-29 and last updated on 2026-10-01.

References

Other CWE-824 vulnerabilities

CVE-2009-0846 — Critical (CVSS 10.0): The asn1_decode_generaltime function in lib/krb5/asn.1/asn1_decode.c in the ASN.1 GeneralizedTime decoder in MIT…
CVE-2007-2442 — Critical (CVSS 10.0): The gssrpc__svcauth_gssapi function in the RPC library in MIT Kerberos 5 (krb5) 1.6.1 and earlier might allow remote…
CVE-2026-2805 — Critical (CVSS 9.8): Invalid pointer in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.
CVE-2026-2785 — Critical (CVSS 9.8): Invalid pointer in the JavaScript Engine component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8,…
CVE-2022-46280 — Critical (CVSS 9.8): A use of uninitialized pointer vulnerability exists in the PQS format pFormat functionality of Open Babel 3.1.1 and…
CVE-2022-44451 — Critical (CVSS 9.8): A use of uninitialized pointer vulnerability exists in the MSI format atom functionality of Open Babel 3.1.1 and master…

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