Security Bulletin
Summary
IBM Watson Speech Services Cartridge is vulnerable to incomplete validation in LangChain, due to flaws in the f-string prompt-template. [CVE-2026-40087]. LangChain is used in our speech runtimes. This vulnerabilitiy has been addressed. Please read the details for remediation below.
Vulnerability Details
CVEID: CVE-2026-40087
DESCRIPTION: LangChain is a framework for building agents and LLM-powered applications. Prior to 0.3.84 and 1.2.28, LangChain's f-string prompt-template validation was incomplete in two respects. First, some prompt template classes accepted f-string templates and formatted them without enforcing the same attribute-access validation as PromptTemplate. In particular, DictPromptTemplate and ImagePromptTemplate could accept templates containing attribute access or indexing expressions and subsequently evaluate those expressions during formatting. Second, f-string validation based on parsed top-level field names did not reject nested replacement fields inside format specifiers. In this pattern, the nested replacement field appears in the format specifier rather than in the top-level field name. As a result, earlier validation based on parsed field names did not reject the template even though Python formatting would still attempt to resolve the nested expression at runtime. This vulnerability is fixed in 0.3.84 and 1.2.28.
CWE: CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine
CVSS Source: security-advisories@github.com
CVSS Base score: 5.3
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N)
Affected Products and Versions
| Affected Product(s) | Version(s) |
| IBM Watson Speech Services Cartridge | 4.0.0 - 5.3.1 |
Remediation/Fixes
| Product(s) | Version(s) | Remediation/Fix/Instructions |
| IBM Watson Speech Services Cartridge | 5.3.1 Patch 7 | The fix in 5.3.1 Patch 7 applies to all versions listed (4.0.0-5.3.1). The newest version of 5.3.1 with the included Patch 7 can be downloaded and installed from: https://www.ibm.com/docs/en/cloud-paks/cp-data/5.3.x |
Workarounds and Mitigations
None
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References
Acknowledgement
Change History
22 Jun 2026: Initial Publication
*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.
Disclaimer
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Document Location
Worldwide
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Document Information
Modified date:
22 June 2026
Initial Publish date:
22 June 2026
UID
ibm17277455