CVE-2026-93894
Description
In Vinyl Cache before 9.0,2, workspace buffer overflow vulnerability was found in the .upper() and .lower() string type methods of VCL. This can be used as a remote denial of service (DoS) vector to make the child process segfault or assert, and then restart. Effectively exploiting this vulnerability requires prior knowledge about the VCL in use and the ability to craft a request that contains a string that is long enough to fill the remaining workspace at the call site while staying under the different request size limits (http_req_size, http_req_hdr_len, etc.).
How to fix
- Vinyl-Cache Vinyl Cache9.0.2, 90f5bacc14b2404e6cc349ba015f0f73b8515136 or later
- Varnish-Software Varnish Cache9.0.4, c5078ae575201b05ae8674a90ddb19ffe7f4b439 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Vinyl-Cache Vinyl Cache | v < 9.0.2, v < 90f5bacc14b2404e6cc349ba015f0f73b8515136 | 9.0.2, 90f5bacc14b2404e6cc349ba015f0f73b8515136 |
| Varnish-Software Varnish Cache | 9.0.0 ≤ v < 9.0.4, v < c5078ae575201b05ae8674a90ddb19ffe7f4b439, 6.3.0 ≤ v ≤ 8.0.2 | 9.0.4, c5078ae575201b05ae8674a90ddb19ffe7f4b439 |
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