TLS authentication bypass in the Erlang/OTP runtime can enable server impersonation and MITM across many backend systems using OTP.
CVE-2026-89422
TLS 1.3 client authentication bypass in Erlang/OTP ssl enabling server impersonation
Is CVE-2026-89422 being exploited?
Not confirmed. CVE-2026-89422 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.46% probability of exploitation in the next 30 days.
How severe is CVE-2026-89422?
CVE-2026-89422 is rated Critical with a CVSS score of 9.3. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-89422?
Yes. A fix has been recorded for CVE-2026-89422. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-89422 affect?
CVE-2026-89422 affects Erlang/OTP versions <27.3.4.18, Erlang/OTP versions <28.5.0.7, Erlang/OTP versions <29.1.1, ssl library releases prior to 11.2.12.13 / 11.6.0.6 / 11.7.7. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-89422?
Upgrade OTP to the fixed versions now; disable TLS1.3 client or block untrusted peers temporarily.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
TLS 1.3 handshake can skip certificate validation allowing attacker server impersonation/MITM and unauthenticated connections.
Immediate action required
- affected>= 22.2 and < *
- affected>= 9.5 and < *
- affected>= 21b8a1b0ad0adf200682b3854bc50114ab2b8c62 and < *
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
cisa ssvc
- exploitation
- none
- automatable
- yes
- technical impact
- total
Assessed by CISA 22 Sept 2026 (SSVC 2.0.3).
timeline
- 22 Sept 2026Published
- 22 Sept 2026Analysed by vulneraibility.com · same day later
- 22 Sept 2026CISA SSVC assessment: exploitation none · same day later
- 22 Sept 2026CVE record last updated · same day later
also known as
- Advisorygithub.com /erlang/otp/security/advisories/GHSA-rgxr-4g4w-j875
- Patchgithub.com /erlang/otp/commit/afec5156361bb50d3607c7c1a453c19b9149b324
- Patchgithub.com /erlang/otp/commit/98c66c858113949c4262d26cd7d426c4b09d2b35
- Patchgithub.com /erlang/otp/commit/fd1d9d07fc92ec0d59f96dfb66182195882bb7dd
- Linkcna.erlef.org /cves/CVE-2026-89422.html
- Linkosv.dev /vulnerability/EEF-CVE-2026-89422
- Linkerlang.org /doc/system/versions.html#order-of-versions
- Linkgithub.com /erlang/otp/commit/21b8a1b0ad0adf200682b3854bc50114ab2b8c62
sources
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- OSV: advisory aliases and downstream package versions
- Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.