VeraCrypt up to 1.26.29 Serialization Serializer.cpp DeserializeWString size/count heap-based overflow

Summaryinfo

A vulnerability was found in VeraCrypt up to 1.26.29. It has been rated as very critical. This vulnerability affects the function Serializer::DeserializeWString of the file src/Platform/Serializer.cpp of the component Serialization. The manipulation of the argument size/count leads to heap-based overflow. This vulnerability is documented as CVE-2026-77372. The attack needs to be performed locally. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in VeraCrypt up to 1.26.29. This issue affects the function Serializer::DeserializeWString of the file src/Platform/Serializer.cpp of the component Serialization. The manipulation of the argument size/count with an unknown input leads to a heap-based overflow vulnerability. Using CWE to declare the problem leads to CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). Impacted is confidentiality, integrity, and availability. The summary by CVE is:

VeraCrypt provides disk encryption with strong security based on TrueCrypt. Prior to 1.26.30, the Unix, macOS, and FreeBSD serialization paths in src/Platform/Serializer.cpp and src/Volume/VolumePassword.cpp accept untrusted length and count values when deserializing data that can cross from the unprivileged GUI or CLI to the root CoreService helper. Serializer::DeserializeWString allocates floor(size / sizeof(wchar_t)) elements but reads size bytes, so a non-aligned size can overflow the heap allocation. VolumePassword::Deserialize accepts PasswordSize values larger than the fixed 128-byte PasswordBuffer, allowing downstream DataPtr() and Size() consumers such as the KDF to read beyond the buffer. DeserializeString, DeserializeWString, and the string and wide-string list readers also lack allocation and collection bounds, which can exhaust memory, and a zero-length DeserializeString can access an empty vector. Windows uses a different path, and the immediate CoreService pipe writer is the same-user parent process, so the documented exposure is a local defense-in-depth boundary rather than a remote attack. This issue is fixed in 1.26.30.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-77372 since 08/20/2026. The exploitation is known to be easy. Attacking locally is a requirement. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 11/05/2026).

Upgrading to version 1.26.30 eliminates this vulnerability.

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Productinfo

Name

• VeraCrypt

Version

• 1.26.0
• 1.26.1
• 1.26.2
• 1.26.3
• 1.26.4
• 1.26.5
• 1.26.6
• 1.26.7
• 1.26.8
• 1.26.9
• 1.26.10
• 1.26.11
• 1.26.12
• 1.26.13
• 1.26.14
• 1.26.15
• 1.26.16
• 1.26.17
• 1.26.18
• 1.26.19
• 1.26.20
• 1.26.21
• 1.26.22
• 1.26.23
• 1.26.24
• 1.26.25
• 1.26.26
• 1.26.27
• 1.26.28
• 1.26.29

Website

• Product: https://github.com/veracrypt/VeraCrypt/

CPE 2.3info

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CPE 2.2info

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