CVE-2025-9556

Status: DeferredCritical (9.8)—

Langchaingo supports the use of jinja2 syntax when parsing prompts, which is in turn parsed using the gonja library v1.5.3. Gonja supports include and extends syntax to read files, which leads to a server side template injection vulnerability within langchaingo, allowing an attacker to insert a statement into a prompt to read the "etc/passwd" file.

CVSS

Version: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Base score: 9.8

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.67%
Percentile among all scored CVEs: 51
Score date: 10/14/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1190 Exploit Public-Facing Applicationinitial access95 %
Secondary impactT1005 Data from Local Systemcollection90 %

Vector AV:N/PR:N/UI:N indica explotación remota sin privilegios (T1190). SSTI en Jinja2/Gonja permite ejecución de código arbitrario y lectura de archivos (/etc/passwd) por inyección en prompts.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Filter Network Traffic Application Isolation and Sandboxing

Affected technologies (2)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Gonja — Gonja^AI Langchaingo — Langchaingo^AI

References

Raw JSON (NVD)

Show

{
  "id": "CVE-2025-9556",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2025-9556",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2025-09-12T14:00:53.431491Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "cret@cert.org",
      "affectedData": [
        {
          "vendor": "Langchaingo",
          "product": "Langchaingo",
          "versions": [
            {
              "status": "affected",
              "version": "0.1.14"
            }
          ]
        }
      ]
    }
  ],
  "published": "2025-09-12T14:15:42.300",
  "references": [
    {
      "url": "https://github.com/tmc/langchaingo/pull/1348",
      "source": "cret@cert.org"
    },
    {
      "url": "https://github.com/tmc/langchaingo/security/advisories/GHSA-mgcj-g55g-rf6h",
      "source": "cret@cert.org"
    },
    {
      "url": "https://www.kb.cert.org/vuls/id/949137",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Deferred",
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    {
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      "value": "Langchaingo supports the use of jinja2 syntax when parsing prompts, which is in turn parsed using the gonja library v1.5.3.\r\nGonja supports include and extends syntax to read files, which leads to a server side template injection vulnerability within langchaingo, allowing an attacker to insert a statement into a prompt to read the \"etc/passwd\" file."
    }
  ],
  "lastModified": "2026-06-17T10:09:12.960",
  "sourceIdentifier": "cret@cert.org"
}