Answer in brief
CVE-2025-37856 records a High severity (CVSS 7.8) vulnerability in btrfs: harden block_group::bg_list against list_del() races. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), 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 7.8. 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), 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 | >=a9f189716cf15913c453299d72f69c51a9b0f86b <bf089c4d1141b27332c092b1dcca5022c415a3b6 || >=a9f189716cf15913c453299d72f69c51a9b0f86b <909e60fb469d4101c6b08cf6e622efb062bb24a1 || >=a9f189716cf15913c453299d72f69c51a9b0f86b <185fd73e5ac06027c4be9a129e59193f6a3ef202 || >=a9f189716cf15913c453299d72f69c51a9b0f86b <7511e29cf1355b2c47d0effb39e463119913e2f6 || edf3b5aadb2515c808200b904baa5b70a727f0ac || 01eca70ef8cf499d0cb6d1bbd691558e7792cf17 || 5d19abcffd8404078dfa7d7118cec357b5e7bc58 || >=5.15.128 <5.16 || >=6.1.47 <6.2 || >=6.4.12 <6.5 | bf089c4d1141b27332c092b1dcca5022c415a3b6, 909e60fb469d4101c6b08cf6e622efb062bb24a1, 185fd73e5ac06027c4be9a129e59193f6a3ef202, 7511e29cf1355b2c47d0effb39e463119913e2f6, 5.16, 6.2, 6.5 |
| Linux/Linuxgeneric | 6.5 | Not reported |
| Linux/Linuxgeneric | >=a9f189716cf15913c453299d72f69c51a9b0f86b <9039afe6240ae01d6caf2fa731590ac74fb8a69b || >=a9f189716cf15913c453299d72f69c51a9b0f86b <bf089c4d1141b27332c092b1dcca5022c415a3b6 || >=a9f189716cf15913c453299d72f69c51a9b0f86b <909e60fb469d4101c6b08cf6e622efb062bb24a1 || >=a9f189716cf15913c453299d72f69c51a9b0f86b <185fd73e5ac06027c4be9a129e59193f6a3ef202 || >=a9f189716cf15913c453299d72f69c51a9b0f86b <7511e29cf1355b2c47d0effb39e463119913e2f6 || edf3b5aadb2515c808200b904baa5b70a727f0ac || 01eca70ef8cf499d0cb6d1bbd691558e7792cf17 || 5d19abcffd8404078dfa7d7118cec357b5e7bc58 || >=5.15.128 <5.16 || >=6.1.47 <6.2 || >=6.4.12 <6.5 | 9039afe6240ae01d6caf2fa731590ac74fb8a69b, bf089c4d1141b27332c092b1dcca5022c415a3b6, 909e60fb469d4101c6b08cf6e622efb062bb24a1, 185fd73e5ac06027c4be9a129e59193f6a3ef202, 7511e29cf1355b2c47d0effb39e463119913e2f6, 5.16, 6.2, 6.5 |
| Linux/Linuxgeneric | >=01eca70ef8cf499d0cb6d1bbd691558e7792cf17 <ccb20413e7c82e4429c81f10d0e36cd9c0c643cd || >=a9f189716cf15913c453299d72f69c51a9b0f86b <9039afe6240ae01d6caf2fa731590ac74fb8a69b || >=a9f189716cf15913c453299d72f69c51a9b0f86b <bf089c4d1141b27332c092b1dcca5022c415a3b6 || >=a9f189716cf15913c453299d72f69c51a9b0f86b <909e60fb469d4101c6b08cf6e622efb062bb24a1 || >=a9f189716cf15913c453299d72f69c51a9b0f86b <185fd73e5ac06027c4be9a129e59193f6a3ef202 || >=a9f189716cf15913c453299d72f69c51a9b0f86b <7511e29cf1355b2c47d0effb39e463119913e2f6 || edf3b5aadb2515c808200b904baa5b70a727f0ac || 5d19abcffd8404078dfa7d7118cec357b5e7bc58 || >=6.1.47 <6.1.191 || >=5.15.128 <5.16 || >=6.4.12 <6.5 | ccb20413e7c82e4429c81f10d0e36cd9c0c643cd, 9039afe6240ae01d6caf2fa731590ac74fb8a69b, bf089c4d1141b27332c092b1dcca5022c415a3b6, 909e60fb469d4101c6b08cf6e622efb062bb24a1, 185fd73e5ac06027c4be9a129e59193f6a3ef202, 7511e29cf1355b2c47d0effb39e463119913e2f6, 6.1.191, 5.16, 6.5 |
Published upstream
May 9, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 30, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
In the Linux kernel, the following vulnerability has been resolved: btrfs: harden block_group::bg_list against list_del() races As far as I can tell, these calls of list_del_init() on bg_list cannot run concurrently with btrfs_mark_bg_unused() or btrfs_mark_bg_to_reclaim(), as they are in transaction error paths and situations where the block group is readonly. However, if there is any chance at all of racing with mark_bg_unused(), or a different future user of bg_list, better to be safe than sorry. Otherwise we risk the following interleaving (bg_list refcount in parens) T1 (some random op) T2 (btrfs_mark_bg_unused) !list_empty(&bg->bg_list); (1) list_del_init(&bg->bg_list); (1) list_move_tail (1) btrfs_put_block_group (0) btrfs_delete_unused_bgs bg = list_first_entry list_del_init(&bg->bg_list); btrfs_put_block_group(bg); (-1) Ultimately, this results in a broken ref count that hits zero one deref early and the real final deref underflows the refcount, resulting in a WARNING.
Quoted source text, attributed separately from HOL analysis.