CVE-2026-42791
Fixed in a distro release EPSS <1%CVSS 6.3
Improper Certificate Validation vulnerability in Erlang OTP public_key (pubkey_ocsp module) allows forged OCSP responses signed with an expired responder certificate to be accepted as valid. OCSP response verification in pubkey_ocsp:verify_response/5 and pubkey_ocsp:is_authorized_responder/3 in lib/public_key/src/pubkey_ocsp.erl does not check the validity period (notBefore/notAfter) of the OCSP responder certificate. An attacker who has obtained the private key of an expired CA-designated OCSP responder certificate can forge OCSP responses that Erlang/OTP accepts as valid. This affects TLS clients using OCSP stapling via the ssl application: a malicious or compromised server can present a revoked TLS certificate together with a forged OCSP response signed by an expired responder key, and the client will accept the revoked certificate as valid. It also affects applications calling public_key:pkix_ocsp_validate/5 directly, where the impact depends on the use case — server-side client certificate validation using this API may allow authentication bypass with a revoked client certificate. This issue affects OTP from OTP 27.0 before OTP 29.0.1, OTP 28.5.0.1 and OTP 27.3.4.12, corresponding to public_key from 1.16 before 1.21.1, 1.20.3.1 and 1.17.1.3.
Products: erlang otp
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Debian 13 | erlang | 1:27.3.4.1+dfsg-1+deb13u3 |
| Debian 14 | erlang | 1:27.3.4.12+dfsg-1 |
| Red Hat hummingbird 1 | erlang27 | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-asn1 | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-common_test | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-compiler | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-crypto | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-debugger | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-dialyzer | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-diameter | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-edoc | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-eldap | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-erl_interface | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-erts | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-et | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-eunit | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-examples | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-ftp | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-gdb-tools | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-inets | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-jinterface | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-kernel | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-megaco | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-mnesia | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-observer | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-odbc | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-os_mon | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-parsetools | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-public_key | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-reltool | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-runtime_tools | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-sasl | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-snmp | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-ssh | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-ssl | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-stdlib | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-syntax_tools | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-tftp | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-tools | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-wx | 0:27.3.4.17-1.hum1 |
| Red Hat hummingbird 1 | erlang27-xmerl | 0:27.3.4.17-1.hum1 |
| SUSE Linux Enterprise Server 16.0 | erlang | 27.1.3-160000.5.1 |
| SUSE Linux Enterprise Server for SAP applications 16.0 | erlang | 27.1.3-160000.5.1 |
| Ubuntu 22.04 LTS | erlang | 1:24.2.1+dfsg-1ubuntu0.8 |
| Ubuntu 24.04 LTS | erlang | 1:25.3.2.8+dfsg-1ubuntu4.8 |
| Ubuntu 25.10 | erlang | no fix |
| Ubuntu 26.04 LTS | erlang | 1:27.3.4.6+dfsg-1ubuntu0.2 |
| Ubuntu Pro 14.04 LTS | erlang | 1:16.b.3-dfsg-1ubuntu2.2+esm3 |
| Ubuntu Pro 16.04 LTS | erlang | 1:18.3-dfsg-1ubuntu3.1+esm4 |
| Ubuntu Pro 18.04 LTS | erlang | 1:20.2.2+dfsg-1ubuntu2+esm4 |
| Ubuntu Pro 20.04 LTS | erlang | 1:22.2.7+dfsg-1ubuntu0.5+esm3 |
| openSUSE Leap 16.0 | erlang | 27.1.3-160000.5.1 |
| openSUSE Tumbleweed | erlang | 28.5.0.4-1.1 |
| openSUSE Tumbleweed | erlang27 | 27.1.3-2.1 |