Answer in brief
CVE-2026-53393 records a Medium severity (CVSS 5.5) vulnerability in nfsd: reset write verifier on deferred writeback errors. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=f14816f2f928c560d28ba344af689f56efcd6f55 <b8e5894e56cff70fa245628fe16f0ad6367f8090 || >=3145fe0ebb16e1715ad541a301bc6675c8375fcd <bc2baca02ec56da7707a74ed5d340b0a1dff1841 || >=555dbf1a9aac6d3150c8b52fa35f768a692f4eeb <43b65d2997963e80e8d8d86520bcb1e0751227de || >=555dbf1a9aac6d3150c8b52fa35f768a692f4eeb <666e837b247fcadf2d8d508b9b0e49d720393eb4 || >=555dbf1a9aac6d3150c8b52fa35f768a692f4eeb <1dd664b39774a9c89b72de8e59bf9ef4b3aaff2e || >=555dbf1a9aac6d3150c8b52fa35f768a692f4eeb <4367afc119c51e17a616f6908772b7e2c2c4013f || >=555dbf1a9aac6d3150c8b52fa35f768a692f4eeb <b027cca33c97354149fcc0ddeede4525c41093cd || >=555dbf1a9aac6d3150c8b52fa35f768a692f4eeb <2090b05803faab8a9fa62fbff871007862cac1b7 || >=5.10.124 <5.10.261 || >=5.15.49 <5.15.212 | b8e5894e56cff70fa245628fe16f0ad6367f8090, bc2baca02ec56da7707a74ed5d340b0a1dff1841, 43b65d2997963e80e8d8d86520bcb1e0751227de, 666e837b247fcadf2d8d508b9b0e49d720393eb4, 1dd664b39774a9c89b72de8e59bf9ef4b3aaff2e, 4367afc119c51e17a616f6908772b7e2c2c4013f, b027cca33c97354149fcc0ddeede4525c41093cd, 2090b05803faab8a9fa62fbff871007862cac1b7, 5.10.261, 5.15.212 |
| Linux/Linuxgeneric | 5.17 | Not reported |
Published upstream
Jul 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 17, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 17, 2026
In the Linux kernel, the following vulnerability has been resolved: nfsd: reset write verifier on deferred writeback errors nfsd_vfs_write() and nfsd_commit() both call filemap_check_wb_err() to detect deferred writeback errors, but neither rotates the server's write verifier (nn->writeverf) when this check fails. Every other durable-storage-failure path in these functions calls commit_reset_write_verifier() before returning an error. The missing rotation means clients holding UNSTABLE write data under the current verifier will COMMIT, receive the unchanged verifier back, and conclude their data is durable — silently dropping data that failed writeback. This violates the UNSTABLE+COMMIT durability contract (RFC 1813 §3.3.7, RFC 8881 §18.32). Add commit_reset_write_verifier() calls at both filemap_check_wb_err() error sites, matching the pattern used by adjacent error paths in the same functions. The helper already filters -EAGAIN and -ESTALE internally, so the calls are unconditionally safe.
Quoted source text, attributed separately from HOL analysis.