Project Subscriptions
No data.
No advisories yet.
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
Thu, 20 Aug 2026 19:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Thu, 20 Aug 2026 18:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | msgpack_unpacker_expand_buffer in src/unpack.c, reached through the public msgpack_unpacker_reserve_buffer API, computes its new buffer size using an unchecked size_t addition of the requested size and the amount already used. The doubling loop guards its own multiplication against overflow, but the addition in the loop condition is unguarded, so a request near SIZE_MAX wraps: the loop condition is already satisfied, the allocation is performed at the small pre-wrap size, and the function returns true. The caller is told the requested capacity was reserved when it was not, so a subsequent write of the requested length overflows the heap buffer. The library's own example/lib_buffer_unpack.c demonstrates the reserve-then-write pattern, and its defensive assert comparing capacity against the request is compiled out under NDEBUG. msgpack-c's own decode entry points do not derive the reservation size from untrusted input, so reaching this requires an integration that passes an attacker-influenced length to the reservation API, such as a length-prefixed streaming transport. | |
| Title | msgpack-c Integer Overflow in msgpack_unpacker_expand_buffer Causes a False-Success Undersized Reservation | |
| Weaknesses | CWE-190 CWE-787 |
|
| References |
|
|
| Metrics |
cvssV3_1
|
Projects
Sign in to view the affected projects.
Status: PUBLISHED
Assigner: VulnCheck
Published:
Updated: 2026-08-20T18:53:26.891Z
Reserved: 2026-08-10T15:16:31.371Z
Link: CVE-2026-72854
Updated: 2026-08-20T18:53:19.871Z
Status : Received
Published: 2026-08-20T19:17:01.040
Modified: 2026-08-20T19:17:01.040
Link: CVE-2026-72854
No data.
OpenCVE Enrichment
No data.