CVE Intelligence
High Injection

CVE-2025-6985 — XXE Vulnerability in langchain-ai/langchain

The HTMLSectionSplitter class in langchain-text-splitters version 0.3.8 is vulnerable to XML External Entity (XXE) attacks due to unsafe XSLT parsing. This vulnerability arises because the class allows the use of arbitrary XSLT stylesheets, which are parsed using lxml.etree.parse() and lxml.etree.XSLT() without any hardening measures. In lxml versions up to 4.9.x, external entities are resolved by default, allowing attackers to read arbitrary local files or perform outbound HTTP(S) fetches. In lxml versions 5.0 and above, while entity expansion is disabled, the XSLT document() function can still read any URI unless XSLTAccessControl is applied. This vulnerability allows remote attackers to gain read-only access to any file the LangChain process can reach, including sensitive files such as SSH keys, environment files, source code, or cloud metadata. No authentication, special privileges, or user interaction are required, and the issue is exploitable in default deployments that enable custom XSLT.

Published Oct 6, 2025 · Updated Oct 19, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: @huntr_ai

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.5% (30-day exploitation probability)+6
  • Technical severity (high)+6
  • CISA SSVC: exploitation "poc"+5
  • Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.51%
ahead of 42% of scored CVEs · Oct 19, 2026
Affects
Langchain-ai
Langchain-ai/langchain and 1 more
CVSS base
7.5
High · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Proof of concept
none · proof-of-concept · active
Automatable
Yes
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Pip Langchain-text-splitters: fixed in version 0.3.9 — github.com (GitHub Security Advisories)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Langchain-ai Langchain-ai/langchain, Pip Langchain-text-splitters).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. Apply the fixed version or the patch documented under Remediation.
  4. Search available logs for exploit probes matching the vulnerability class (injection), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Langchain-ai Langchain-ai/langchain ≤ latest Vulnerable CVE Program (cve.org) e CISA ADP
Pip Langchain-text-splitters < 0.3.9 Vulnerable GitHub Security Advisories

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
7.5 CVSS 3.0 High 3.9 3.6 security@huntr.dev via NIST National Vulnerability Database
7.5 CVSS 3.0 High — — GitHub, Inc. via GitHub Security Advisories
7.5 CVSS 3.0 High — — @huntr_ai via CVE Program (cve.org) e CISA ADP
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N (score shown at the top: security@huntr.dev)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-611 · XML External Entity (XXE)

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Look for parameters with command/query metacharacters and unexpected child processes of the service.
web/proxy/WAF logsnetwork IDS/IPSapplication logsendpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

  • 2026
  • Fix documented
    Oct 19, 2026 · GitHub Security Advisories
  • Affected products added · pip/langchain-text-splitters
    Oct 19, 2026 · GitHub Security Advisories
  • Affected products added · langchain-ai/langchain-ai/langchain
    Oct 19, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 19, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 19, 2026
  • CVSS changed · 7.5
    Oct 19, 2026 · NIST National Vulnerability Database
  • Source status changed · → Deferred
    Oct 19, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 19, 2026 · NIST National Vulnerability Database
  • 2025
  • CVE published
    Oct 6, 2025 · @huntr_ai

Source activity

Repeated readings are counted rather than listed.

  • 1× References added · Oct 19, 2026 – Oct 19, 2026
  • 1× Official description updated · Oct 19, 2026 – Oct 19, 2026

References

5 on the record

Elsewhere on this site

Langchain-ai
every CVE for this vendor
Injection
same class
CWE-611
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-55443 LangChain: Path traversal and sandbox escape in LangChain file-search middleware and loaders Jun 22, 2026
  • CVE-2026-44843 LangChain: Unsafe deserialization of attacker-controlled LangChain objects through overly broad `load()` allowlists May 26, 2026
  • CVE-2026-40087 LangChain has incomplete f-string validation in prompt templates Apr 9, 2026
  • CVE-2026-34070 LangChain Core has Path Traversal vulnerabilites in legacy `load_prompt` functions Mar 31, 2026
  • CVE-2026-26013 LangChain affected by SSRF via image_url token counting in ChatOpenAI.get_num_tokens_from_messages Feb 10, 2026
  • CVE-2024-58340 LangChain <= 0.3.1 MRKLOutputParser ReDoS Jan 12, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2025-6985 is "XXE Vulnerability in langchain-ai/langchain", rated High. It affects Langchain-ai/langchain (Langchain-ai); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 0.51% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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