UBUNTU-CVE-2026-42791

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Source
https://ubuntu.com/security/CVE-2026-42791
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42791.json
JSON Data
https://api.test.osv.dev/v1/vulns/UBUNTU-CVE-2026-42791
Upstream
Downstream
Related
Published
2026-05-27T14:16:00Z
Modified
2026-10-08T19:46:17Z
Severity
  • 6.3 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N CVSS Calculator
  • 3.7 (Low) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

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.

References

Affected packages

Ubuntu:25.10 / erlang

Package

Name
erlang
Purl
pkg:deb/ubuntu/erlang?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

1:27.*
1:27.3+dfsg-1ubuntu1
1:27.3+dfsg-1ubuntu1.1
1:27.3.4.1+dfsg-1
1:27.3.4.1+dfsg-1build1
1:27.3.4.1+dfsg-1ubuntu0.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "erlang",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-asn1",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-base",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-common-test",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-crypto",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-debugger",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-dialyzer",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-diameter",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-edoc",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-eldap",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-et",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-eunit",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-examples",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-ftp",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-inets",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-jinterface",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-megaco",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-mnesia",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-mode",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-nox",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-observer",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-odbc",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-os-mon",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-parsetools",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-public-key",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-reltool",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-runtime-tools",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-snmp",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-src",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-ssh",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-ssl",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-syntax-tools",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-tftp",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-tools",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-wx",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-x11",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        },
        {
            "binary_name": "erlang-xmerl",
            "binary_version": "1:27.3.4.1+dfsg-1ubuntu0.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42791.json"

Ubuntu:26.04:LTS / erlang

Package

Name
erlang
Purl
pkg:deb/ubuntu/erlang?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
1:27.3.4.6+dfsg-1ubuntu0.2

Affected versions

1:27.*
1:27.3.4.1+dfsg-1build1
1:27.3.4.3+dfsg-1
1:27.3.4.4+dfsg-1
1:27.3.4.6+dfsg-1
1:27.3.4.6+dfsg-1ubuntu0.1

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "erlang",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-asn1",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-base",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-common-test",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-crypto",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-debugger",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-dialyzer",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-diameter",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-edoc",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-eldap",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-et",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-eunit",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-examples",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-ftp",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-inets",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-jinterface",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-megaco",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-mnesia",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-mode",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-nox",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-observer",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-odbc",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-os-mon",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-parsetools",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-public-key",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-reltool",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-runtime-tools",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-snmp",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-src",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-ssh",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-ssl",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-syntax-tools",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-tftp",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-tools",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-wx",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-x11",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        },
        {
            "binary_name": "erlang-xmerl",
            "binary_version": "1:27.3.4.6+dfsg-1ubuntu0.2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42791.json"