Source: wabt Version: 1.0.41+dfsg+~cs1.0.39-2 Severity: important Tags: security upstream Forwarded: https://github.com/WebAssembly/wabt/issues/2831 X-Debbugs-Cc: [email protected], Debian Security Team <[email protected]>
Hi, The following vulnerability was published for wabt. CVE-2026-90648[0]: | wasm2c in WebAssembly wabt through 1.0.41 allows sandbox escape in | some situations that primarily involve 32-bit platforms, aka a | "table flip" attack. It does not check the return value of calloc() | in wasm_rt_allocate_funcref_table() (wasm2c/wasm-rt-impl- | tableops.inc). When the funcref table allocation fails, table->data | is left NULL while table->size keeps the guest-declared element | count; thus, bounds checks still pass and table element accesses | resolve to absolute memory addresses (i * | sizeof(wasm_rt_funcref_t)). This gives arbitrary read and write of | host process memory and - via table.get, table.set, and | call_indirect - arbitrary code execution, defeating the isolation | that wasm2c exists to provide (a full sandbox escape). wasm2c is | used as an in-process sandboxing boundary by RLBox and WasmBoxC, | including in Firefox, which compiles the Graphite, Hunspell, Ogg, | Expat, and Woff2 libraries via wasm2c to contain untrusted font, | media, and XML input. Therefore, sandboxing in these applications is | potentially affected. Exploitation requires the funcref table | allocation to fail, for example under an address-space limit | (RLIMIT_AS), on 32-bit hosts, with vm.overcommit_memory=2, or under | memory pressure. On 64-bit Linux with default overcommit the | allocation succeeds and the defect is not triggered. The wasm2c | memory allocator aborts on calloc failure in the same runtime; the | table allocator lacks this abort behavior. This was introduced in | commit ab9e0b55 (PR #813). If you fix the vulnerability please also make sure to include the CVE (Common Vulnerabilities & Exposures) id in your changelog entry. For further information see: [0] https://security-tracker.debian.org/tracker/CVE-2026-90648 https://www.cve.org/CVERecord?id=CVE-2026-90648 [1] https://github.com/WebAssembly/wabt/issues/2831 [2] https://github.com/WebAssembly/wabt/issues/2854 [3] https://github.com/WebAssembly/wabt/commit/e197d0b7bd3fe426f5963ae540f4426a1d49e89f Please adjust the affected versions in the BTS as needed. Regards, Salvatore
