CVE-2024-1455
Billion Laughs Attack leading to DoS in langchain-ai/langchain
A vulnerability in the langchain-ai/langchain repository allows for a Billion Laughs Attack, a type of XML External Entity (XXE) exploitation. By nesting multiple layers of entities within an XML document, an attacker can cause the XML parser to consume excessive CPU and memory resources, leading to a denial of service (DoS).
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
5.9
Billion Laughs Attack leading to DoS in langchain-ai/langchain
A vulnerability in the langchain-ai/langchain repository allows for a Billion Laughs Attack, a type of XML External Entity (XXE) exploitation. By nesting multiple layers of entities within an XML document, an attacker can cause the XML parser to consume excessive CPU and memory resources, leading to a denial of service (DoS).
- Record
CVE-2024-1455- CVSS 3.0
- 5.9 Medium
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-776
- Updated
- 2026-11-02
EUVDEUVD-2024-0987
5.9
A vulnerability in the langchain-ai/langchain repository allows for a Billion Laughs Attack, a type of XML External Entity (XXE) exploitation. By nesting multiple layers of entities within an XML document, an attacker can cause the XML parser to consume excessive CPU and memory resources, leading to a denial of service (DoS).
- Record
EUVD-2024-0987- CVSS 3.0
- 5.9 Medium
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-q84m-rmw3-4382
5.9
LangChain's XMLOutputParser vulnerable to XML Entity Expansion
The XMLOutputParser in LangChain uses the etree module from the XML parser in the standard python library which has some XML vulnerabilities; see: https://docs.python.org/3/library/xml.html
This primarily affects users that combine an LLM (or agent) with the XMLOutputParser and expose the component via an endpoint on a web-service.
This would allow a malicious party to attempt to manipulate the LLM to produce a malicious payload for the parser that would compromise the availability of the service.
A successful attack is predicated on:
- Usage of XMLOutputParser
- Passing of malicious input into the XMLOutputParser either directly or by trying to manipulate an LLM to do so on the users behalf
- Exposing the component via a web-service
- Record
GHSA-q84m-rmw3-4382- CVSS 3.0
- 5.9 Medium
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-776
- Updated
- 2026-11-02
NVD
5.9
A vulnerability in the langchain-ai/langchain repository allows for a Billion Laughs Attack, a type of XML External Entity (XXE) exploitation. By nesting multiple layers of entities within an XML document, an attacker can cause the XML parser to consume excessive CPU and memory resources, leading to a denial of service (DoS).
- Record
CVE-2024-1455- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 3.0
- 5.9 Medium
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-776
- Updated
- 2026-11-02
OSV
5.9
Billion Laughs Attack leading to DoS in langchain-ai/langchain
A vulnerability in the langchain-ai/langchain repository allows for a Billion Laughs Attack, a type of XML External Entity (XXE) exploitation. By nesting multiple layers of entities within an XML document, an attacker can cause the XML parser to consume excessive CPU and memory resources, leading to a denial of service (DoS).
- Record
CVE-2024-1455- CVSS 3.0
- 5.9 Medium
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-776
- Updated
- 2026-11-02
OSVGHSA-q84m-rmw3-4382
5.9
LangChain's XMLOutputParser vulnerable to XML Entity Expansion
The XMLOutputParser in LangChain uses the etree module from the XML parser in the standard python library which has some XML vulnerabilities; see: https://docs.python.org/3/library/xml.html
This primarily affects users that combine an LLM (or agent) with the XMLOutputParser and expose the component via an endpoint on a web-service.
This would allow a malicious party to attempt to manipulate the LLM to produce a malicious payload for the parser that would compromise the availability of the service.
A successful attack is predicated on:
- Usage of XMLOutputParser
- Passing of malicious input into the XMLOutputParser either directly or by trying to manipulate an LLM to do so on the users behalf
- Exposing the component via a web-service
- Record
GHSA-q84m-rmw3-4382- CVSS 3.0
- 5.9 Medium
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-776
- Updated
- 2026-11-02
OSVPYSEC-2026-1519
5.9
LangChain's XMLOutputParser vulnerable to XML Entity Expansion
The XMLOutputParser in LangChain uses the etree module from the XML parser in the standard python library which has some XML vulnerabilities; see: https://docs.python.org/3/library/xml.html
This primarily affects users that combine an LLM (or agent) with the XMLOutputParser and expose the component via an endpoint on a web-service.
This would allow a malicious party to attempt to manipulate the LLM to produce a malicious payload for the parser that would compromise the availability of the service.
A successful attack is predicated on:
- Usage of XMLOutputParser
- Passing of malicious input into the XMLOutputParser either directly or by trying to manipulate an LLM to do so on the users behalf
- Exposing the component via a web-service
- Record
PYSEC-2026-1519- CVSS 3.0
- 5.9 Medium
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
langchain-corePyPI |
before 0.1.35 | 0.1.35 |
langchain-corePyPI |
before 0.1.35, plus listed versions 0.0.10.0.100.0.110.0.120.0.13 Show 45 moreShow less0.0.13rc10.0.13rc20.0.20.0.30.0.40.0.50.0.60.0.70.0.80.0.90.1.00.1.10.1.100.1.110.1.120.1.12rc10.1.130.1.140.1.150.1.15rc10.1.15rc20.1.160.1.170.1.180.1.190.1.20.1.200.1.210.1.220.1.230.1.240.1.250.1.260.1.270.1.280.1.290.1.30.1.300.1.310.1.320.1.330.1.33rc10.1.340.1.40.1.5 |
0.1.35 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2024-1455 is a medium vulnerability (CVSS 5.9) in Langchain, published March 26, 2024. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.76%, the 55th percentile. Fixed in langchain-core 0.1.35.
References
huntr.com/bounties/4353571f-c70d-4bfd-ac08-3a89cecb45b6
github.com/langchain-ai/langchain/commit/727d5023ce88e18e3074ef620a98137d26ff92a3
nvd.nist.gov/vuln/detail/CVE-2024-1455
github.com/langchain-ai/langchain/pull/17250
github.com/langchain-ai/langchain/pull/19653
github.com/langchain-ai/langchain/pull/19660
Left out here: 4 versions. The JSON record has them.