RebeccaStevens deepmerge-ts up to 7.x stack-based overflow

Summaryinfo

A vulnerability identified as problematic has been detected in RebeccaStevens deepmerge-ts up to 7.x. This impacts the function deepmerge/deepmergeCustom/deepmergeInto/deepmergeIntoCustom. This manipulation causes stack-based overflow. This vulnerability is tracked as CVE-2026-40345. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability classified as problematic was found in RebeccaStevens deepmerge-ts up to 7.x. Affected by this vulnerability is the function deepmerge/deepmergeCustom/deepmergeInto/deepmergeIntoCustom. The manipulation with an unknown input leads to a stack-based overflow vulnerability. The CWE definition for the vulnerability is CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). As an impact it is known to affect availability. The summary by CVE is:

deepmerge-ts is a typescript library providing functionality to deep merging of javascript objects. Prior to 8.0.0, the deepmerge, deepmergeCustom, deepmergeInto, and deepmergeIntoCustom APIs do not track visited objects or object pairs when recursively merging records. When two input values contain self-references at the same property path, the merge logic repeatedly revisits the same pair until Node.js raises RangeError: Maximum call stack size exceeded. Applications that merge attacker-controlled recursive object graphs can synchronously crash the affected process or cause repeated worker restarts. Plain JSON input alone cannot create the recursive graph required to trigger the issue. This issue is fixed in version 8.0.0.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-40345 since 04/11/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 8.0.0 eliminates this vulnerability.

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Productinfo

Vendor

• RebeccaStevens

Name

• deepmerge-ts

Version

• 7.x

Website

• Product: https://github.com/RebeccaStevens/deepmerge-ts/

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