CVE-2026-65636

Source
https://cve.org/CVERecord?id=CVE-2026-65636
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-65636.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-65636
Aliases
Published
2026-07-31T13:29:31.198Z
Modified
2026-08-02T03:47:32.875737747Z
Severity
  • 2.1 (Low) CVSS_V4 - CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N CVSS Calculator
Summary
YAML injection via unescaped newlines in ymlr document comments
Details

Improper Neutralization of CRLF Sequences vulnerability in ufirstgroup ymlr (Elixir.Ymlr module) allows attackers to inject arbitrary content into generated YAML documents through document comments. Ymlr.document!/2 interpolates each caller-supplied comment string into the output behind a single # prefix without validating it or escaping line breaks. Because a YAML comment is terminated by a line break, the first carriage return or line feed in the comment string ends the comment context and everything after it is emitted at column 0 of the document body.

An attacker who controls text that the host application passes as a comment can forge top-level mapping keys, override values the application itself set, and emit --- or ... markers that split the output into additional documents. Downstream consumers of the generated YAML, such as configuration loaders, deployment manifests, CI pipelines and data importers, parse the injected content as legitimate data. The same clause backs Ymlr.document/2, Ymlr.documents!/2 and Ymlr.documents/2, so every document encoding entry point is affected.

This vulnerability is associated with program files lib/ymlr.ex and program routines 'Elixir.Ymlr':document!/2, 'Elixir.Ymlr':documents!/2.

This issue affects ymlr from 0.0.1 before 5.1.6.

Database specific
{
    "cwe_ids": [
        "CWE-93"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/65xxx/CVE-2026-65636.json",
    "cna_assigner": "EEF",
    "unresolved_ranges": [
        {
            "source": "AFFECTED_FIELD",
            "extracted_events": [
                {
                    "introduced": "0c11a86de83825e91c27cecaccb03f36416d8fe0"
                },
                {
                    "fixed": "42a0bf8b2af44b0e7c42d0b7044c8588ca5866dc"
                }
            ]
        }
    ]
}
References

Affected packages

Git / github.com/ufirstgroup/ymlr

Affected ranges

Type
GIT
Repo
https://github.com/ufirstgroup/ymlr
Events
Database specific
{
    "source": [
        "DESCRIPTION",
        "REFERENCES"
    ],
    "extracted_events": [
        {
            "introduced": "0.0.1"
        },
        {
            "fixed": "5.1.6"
        }
    ]
}

Affected versions

v0.*
v0.0.1
v1.*
v1.0.0
v1.0.1
v2.*
v2.0.0
v3.*
v3.0.0
v3.0.1
v4.*
v4.0.0
v4.1.0
v4.2.0
v5.*
v5.0.0
v5.1.0
v5.1.1
v5.1.2
v5.1.3
v5.1.4
v5.1.5

Database specific

source
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-65636.json"