Answer in brief
CVE-2021-47636 records a Unknown severity vulnerability in ubifs: Fix read out-of-bounds in ubifs_wbuf_write_nolock(). 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.
A CVSS score is not reported in the current record. 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.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=1e51764a3c2ac05a23a22b2a95ddee4d9bffb16d <5343575aa11c5d7044107d59d43f84aec01312b0 || >=1e51764a3c2ac05a23a22b2a95ddee4d9bffb16d <b80ccbec0e4804436c382d7dd60e943c386ed83a || >=1e51764a3c2ac05a23a22b2a95ddee4d9bffb16d <07a209fadee7b53b46858538e1177597273862e4 || >=1e51764a3c2ac05a23a22b2a95ddee4d9bffb16d <a7054aaf1909cf40489c0ec1b728fdcf79c751a6 || >=1e51764a3c2ac05a23a22b2a95ddee4d9bffb16d <e09fa5318d51f522e1af4fbaf8f74999355980c8 || >=1e51764a3c2ac05a23a22b2a95ddee4d9bffb16d <3b7fb89135a20587d57f8877c02e25003e9edbdf || >=1e51764a3c2ac05a23a22b2a95ddee4d9bffb16d <4f2262a334641e05f645364d5ade1f565c85f20b | 5343575aa11c5d7044107d59d43f84aec01312b0, b80ccbec0e4804436c382d7dd60e943c386ed83a, 07a209fadee7b53b46858538e1177597273862e4, a7054aaf1909cf40489c0ec1b728fdcf79c751a6, e09fa5318d51f522e1af4fbaf8f74999355980c8, 3b7fb89135a20587d57f8877c02e25003e9edbdf, 4f2262a334641e05f645364d5ade1f565c85f20b |
| Linux/Linuxgeneric | 2.6.27 | Not reported |
Published upstream
Feb 26, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 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: ubifs: Fix read out-of-bounds in ubifs_wbuf_write_nolock() Function ubifs_wbuf_write_nolock() may access buf out of bounds in following process: ubifs_wbuf_write_nolock(): aligned_len = ALIGN(len, 8); // Assume len = 4089, aligned_len = 4096 if (aligned_len <= wbuf->avail) ... // Not satisfy if (wbuf->used) { ubifs_leb_write() // Fill some data in avail wbuf len -= wbuf->avail; // len is still not 8-bytes aligned aligned_len -= wbuf->avail; } n = aligned_len >> c->max_write_shift; if (n) { n <<= c->max_write_shift; err = ubifs_leb_write(c, wbuf->lnum, buf + written, wbuf->offs, n); // n > len, read out of bounds less than 8(n-len) bytes } , which can be catched by KASAN: ========================================================= BUG: KASAN: slab-out-of-bounds in ecc_sw_hamming_calculate+0x1dc/0x7d0 Read of size 4 at addr ffff888105594ff8 by task kworker/u8:4/128 Workqueue: writeback wb_workfn (flush-ubifs_0_0) Call Trace: kasan_report.cold+0x81/0x165 nand_write_page_swecc+0xa9/0x160 ubifs_leb_write+0xf2/0x1b0 [ubifs] ubifs_wbuf_write_nolock+0x421/0x12c0 [ubifs] write_head+0xdc/0x1c0 [ubifs] ubifs_jnl_write_inode+0x627/0x960 [ubifs] wb_workfn+0x8af/0xb80 Function ubifs_wbuf_write_nolock() accepts that parameter 'len' is not 8 bytes aligned, the 'len' represents the true length of buf (which is allocated in 'ubifs_jnl_xxx', eg. ubifs_jnl_write_inode), so ubifs_wbuf_write_nolock() must handle the length read from 'buf' carefully to write leb safely. Fetch a reproducer in [Link].
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2021-47636 records a Unknown severity vulnerability in ubifs: Fix read out-of-bounds in ubifs_wbuf_write_nolock(). 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.
A CVSS score is not reported in the current record. 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.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=1e51764a3c2ac05a23a22b2a95ddee4d9bffb16d <5343575aa11c5d7044107d59d43f84aec01312b0 || >=1e51764a3c2ac05a23a22b2a95ddee4d9bffb16d <b80ccbec0e4804436c382d7dd60e943c386ed83a || >=1e51764a3c2ac05a23a22b2a95ddee4d9bffb16d <07a209fadee7b53b46858538e1177597273862e4 || >=1e51764a3c2ac05a23a22b2a95ddee4d9bffb16d <a7054aaf1909cf40489c0ec1b728fdcf79c751a6 || >=1e51764a3c2ac05a23a22b2a95ddee4d9bffb16d <e09fa5318d51f522e1af4fbaf8f74999355980c8 || >=1e51764a3c2ac05a23a22b2a95ddee4d9bffb16d <3b7fb89135a20587d57f8877c02e25003e9edbdf || >=1e51764a3c2ac05a23a22b2a95ddee4d9bffb16d <4f2262a334641e05f645364d5ade1f565c85f20b | 5343575aa11c5d7044107d59d43f84aec01312b0, b80ccbec0e4804436c382d7dd60e943c386ed83a, 07a209fadee7b53b46858538e1177597273862e4, a7054aaf1909cf40489c0ec1b728fdcf79c751a6, e09fa5318d51f522e1af4fbaf8f74999355980c8, 3b7fb89135a20587d57f8877c02e25003e9edbdf, 4f2262a334641e05f645364d5ade1f565c85f20b |
| Linux/Linuxgeneric | 2.6.27 | Not reported |
Published upstream
Feb 26, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 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: ubifs: Fix read out-of-bounds in ubifs_wbuf_write_nolock() Function ubifs_wbuf_write_nolock() may access buf out of bounds in following process: ubifs_wbuf_write_nolock(): aligned_len = ALIGN(len, 8); // Assume len = 4089, aligned_len = 4096 if (aligned_len <= wbuf->avail) ... // Not satisfy if (wbuf->used) { ubifs_leb_write() // Fill some data in avail wbuf len -= wbuf->avail; // len is still not 8-bytes aligned aligned_len -= wbuf->avail; } n = aligned_len >> c->max_write_shift; if (n) { n <<= c->max_write_shift; err = ubifs_leb_write(c, wbuf->lnum, buf + written, wbuf->offs, n); // n > len, read out of bounds less than 8(n-len) bytes } , which can be catched by KASAN: ========================================================= BUG: KASAN: slab-out-of-bounds in ecc_sw_hamming_calculate+0x1dc/0x7d0 Read of size 4 at addr ffff888105594ff8 by task kworker/u8:4/128 Workqueue: writeback wb_workfn (flush-ubifs_0_0) Call Trace: kasan_report.cold+0x81/0x165 nand_write_page_swecc+0xa9/0x160 ubifs_leb_write+0xf2/0x1b0 [ubifs] ubifs_wbuf_write_nolock+0x421/0x12c0 [ubifs] write_head+0xdc/0x1c0 [ubifs] ubifs_jnl_write_inode+0x627/0x960 [ubifs] wb_workfn+0x8af/0xb80 Function ubifs_wbuf_write_nolock() accepts that parameter 'len' is not 8 bytes aligned, the 'len' represents the true length of buf (which is allocated in 'ubifs_jnl_xxx', eg. ubifs_jnl_write_inode), so ubifs_wbuf_write_nolock() must handle the length read from 'buf' carefully to write leb safely. Fetch a reproducer in [Link].
Quoted source text, attributed separately from HOL analysis.