Upstream information
Description
Improper Certificate Validation vulnerability in Erlang OTP public_key (pubkey_cert and public_key modules) allows a DNS nameConstraints bypass via subject CommonName fallback in TLS hostname verification.Two flaws combine to allow a subordinate CA whose DNS nameConstraints are restricted (e.g. permitted;DNS:allowed.example.com) to issue a leaf certificate that an OTP TLS client accepts as a valid identity for an out-of-scope hostname (e.g. victim.example.com):
First, pubkey_cert:validate_names/6 in lib/public_key/src/pubkey_cert.erl only checks SAN DNS entries against nameConstraints. Per RFC 5280, a permitted DNS subtree only restricts certificates that contain a DNS-typed name. A leaf with no subjectAltName therefore trivially satisfies any permitted;DNS:... constraint regardless of its subject commonName.
Second, public_key:pkix_verify_hostname/3 in lib/public_key/src/public_key.erl falls back to the subject commonName when no subjectAltName is present, extracting id-at-commonName attributes as presented IDs and matching them against the reference hostname. The strict pkix_verify_hostname_match_fun(https) matcher does not suppress this fallback.
The result is that path validation accepts a CN-only leaf under a DNS-constrained intermediate (no SAN means the nameConstraints are not triggered), and hostname verification then accepts it via the CN fallback. The bypass is reachable from stock ssl:connect with verify_peer, a trusted CA, SNI, and the canonical strict https hostname matcher.
This issue affects OTP from OTP 19.3 before OTP 26.2.5.21, 27.3.4.12, 28.5.0.1, and 29.0.1 corresponding to public_key from 1.4 before 1.15.1.7, 1.17.1.3, 1.20.3.1, and 1.21.1.
SUSE information
Overall state of this security issue: Pending
This issue is currently rated as having important severity.
| CVSS detail | SUSE |
|---|---|
| Base Score | 7.4 |
| Vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
| Attack Vector | Network |
| Attack Complexity | High |
| Privileges Required | None |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality Impact | High |
| Integrity Impact | High |
| Availability Impact | None |
| CVSSv3 Version | 3.1 |
| CVSS detail | CNA (6b3ad84c-e1a6-4bf7-a703-f496b71e49db) | SUSE |
|---|---|---|
| Base Score | 7.6 | 9.1 |
| Vector | CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N |
| Attack Vector | Network | Network |
| Attack Complexity | High | High |
| Attack Requirements | Present | Present |
| Privileges Required | None | None |
| User Interaction | Passive | None |
| Vulnerable System Confidentiality Impact | High | High |
| Vulnerable System Integrity Impact | High | High |
| Vulnerable System Availability Impact | None | None |
| Subsequent System Confidentiality Impact | None | None |
| Subsequent System Integrity Impact | None | None |
| Subsequent System Availability Impact | None | None |
| CVSSv4 Version | 4.0 | 4.0 |
Status of this issue by product and package
Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification. The updates are grouped by state of their lifecycle. SUSE product lifecycles are documented on the lifecycle page.
| Product(s) | Source package | State |
|---|---|---|
| Products under general support and receiving all security fixes. | ||
| SUSE Linux Enterprise High Performance Computing 15 SP7 | erlang | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP7 | erlang26 | Affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP7 | erlang | Affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP7 | erlang26 | Affected |
| SUSE Linux Enterprise Server 15 SP7 | erlang | Affected |
| SUSE Linux Enterprise Server 15 SP7 | erlang26 | Affected |
| SUSE Linux Enterprise Server 16.0 | erlang | Affected |
| SUSE Linux Enterprise Server 16.1 | erlang | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | erlang | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | erlang26 | Affected |
| SUSE Linux Enterprise Server for SAP applications 16.0 | erlang | Affected |
| SUSE Linux Enterprise Server for SAP applications 16.1 | erlang | Affected |
| openSUSE Leap 16.0 | erlang | Affected |
| Products under Long Term Service Pack support and receiving important and critical security fixes. | ||
| SUSE Linux Enterprise High Performance Computing 15 SP4 | erlang | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | erlang | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5 | erlang | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | erlang | Affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP4 | erlang | Affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP5 | erlang | Affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP6 | erlang | Affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP6 | erlang26 | Affected |
| SUSE Linux Enterprise Server 15 SP4 | erlang | Affected |
| SUSE Linux Enterprise Server 15 SP4-LTSS | erlang | Affected |
| SUSE Linux Enterprise Server 15 SP5 | erlang | Affected |
| SUSE Linux Enterprise Server 15 SP5-LTSS | erlang | Affected |
| SUSE Linux Enterprise Server 15 SP6 | erlang | Affected |
| SUSE Linux Enterprise Server 15 SP6 | erlang26 | Affected |
| SUSE Linux Enterprise Server 15 SP6-LTSS | erlang | Affected |
| SUSE Linux Enterprise Server 15 SP6-LTSS | erlang26 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | erlang | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | erlang26 | Affected |
| SUSE Manager Proxy 4.3 | erlang | Affected |
| SUSE Manager Proxy LTS 4.3 | erlang | Affected |
| SUSE Manager Retail Branch Server 4.3 | erlang | Affected |
| SUSE Manager Retail Branch Server LTS 4.3 | erlang | Affected |
| SUSE Manager Server 4.3 | erlang | Affected |
| SUSE Manager Server LTS 4.3 | erlang | Affected |
| Products past their end of life and not receiving proactive updates anymore. | ||
| SUSE Enterprise Storage 7 | erlang | Affected |
| SUSE Enterprise Storage 7.1 | erlang | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2 | erlang | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-ESPOS | erlang | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS | erlang | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3 | erlang | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-ESPOS | erlang | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS | erlang | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | erlang | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS | erlang | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP6 | erlang | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP6 | erlang26 | Affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP2 | erlang | Affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP3 | erlang | Affected |
| SUSE Linux Enterprise Real Time 15 SP2 | erlang | Affected |
| SUSE Linux Enterprise Real Time 15 SP3 | erlang | Affected |
| SUSE Linux Enterprise Real Time 15 SP4 | erlang | Affected |
| SUSE Linux Enterprise Server 15 SP2 | erlang | Affected |
| SUSE Linux Enterprise Server 15 SP2-BCL | erlang | Affected |
| SUSE Linux Enterprise Server 15 SP2-LTSS | erlang | Affected |
| SUSE Linux Enterprise Server 15 SP3 | erlang | Affected |
| SUSE Linux Enterprise Server 15 SP3-BCL | erlang | Affected |
| SUSE Linux Enterprise Server 15 SP3-LTSS | erlang | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP2 | erlang | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP3 | erlang | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | erlang | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | erlang | Affected |
| SUSE Manager Proxy 4.1 | erlang | Affected |
| SUSE Manager Proxy 4.2 | erlang | Affected |
| SUSE Manager Retail Branch Server 4.1 | erlang | Affected |
| SUSE Manager Retail Branch Server 4.2 | erlang | Affected |
| SUSE Manager Server 4.1 | erlang | Affected |
| SUSE Manager Server 4.2 | erlang | Affected |
| openSUSE Leap 15.3 | erlang | Affected |
| openSUSE Leap 15.4 | erlang | Affected |
| openSUSE Leap 15.5 | erlang | Affected |
| openSUSE Leap 15.6 | erlang | Affected |
| openSUSE Leap 15.6 | erlang26 | Affected |
SUSE Timeline for this CVE
CVE page created: Wed May 27 20:03:39 2026CVE page last modified: Thu May 28 11:41:38 2026