Nixpkgs security tracker

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Permalink CVE-2026-49263

2.0 LOW

CVSS version (CVSS): 4.0
Attack Vector (AV): Local (L)
Attack Complexity (AC): Low (L)
Attack Requirement (AT): Present (P)
Privileges Required (PR): None (N)
User Interaction (UI): Passive (P)
Vulnerable System Impact Confidentiality (VC): None (N)
Vulnerable System Impact Integrity (VI): Low (L)
Vulnerable System Impact Availability (VA): Low (L)
Subsequent System Impact Confidentiality (SC): None (N)
Subsequent System Impact Integrity (SI): None (N)
Subsequent System Impact Availability (SA): None (N)
Modified Attack Vector (MAV): Local (L)
Modified Attack Complexity (MAC): Low (L)
Modified Attack Requirement (MAT): Present (P)
Modified Privileges Required (MPR): None (N)
Modified User Interaction (MUI): Passive (P)
Modified Vulnerable System Impact Confidentiality (MVC): None (N)
Modified Vulnerable System Impact Integrity (MVI): Low (L)
Modified Vulnerable System Impact Availability (MVA): Low (L)
Modified Subsequent System Impact Confidentiality (MSC): Negligible (N)
Modified Subsequent System Impact Integrity (MSI): Negligible (N)
Modified Subsequent System Impact Availability (MSA): Negligible (N)
Safety (S): Not Defined (X)
Automatable (AU): Not Defined (X)
Recovery (R): Not Defined (X)
Value Density (V): Not Defined (X)
Vulnerability Response Effort (RE): Not Defined (X)
Provider Urgency (U): Not Defined (X)
Confidentiality Req. (CR): Not Defined (X)
Integrity Req. (IR): Not Defined (X)
Availability Req. (AR): Not Defined (X)
Exploit Maturity (E): Not Defined (X)

created 2 weeks, 2 days ago Activity log

Created suggestion 2 weeks, 2 days ago

Capstone WASM `br_table` instruction-size truncation can cause no-progress disassembly and parser desynchronization

Capstone is a disassembly framework. Prior to version 6.0.0-Alpha9, Capstone's WebAssembly backend accepts attacker-controlled raw WASM instruction bytes through the public `cs_disasm()` and `cs_disasm_iter()` APIs. For a large but well-formed `br_table` instruction, the WASM decoder accumulates the immediate length in a wider local variable but returns it through a `uint16_t` instruction-size path. When the encoded instruction length is exactly 65,536 bytes, the size wraps to zero and `cs_disasm()` can repeatedly decode the same instruction without advancing. For larger lengths, `cs_disasm_iter()` advances into the middle of the `br_table` payload and decodes target bytes as subsequent instructions. This is an availability and parser-integrity issue. Version 6.0.0-Alpha9 patches the issue.