afs: Fix page leak
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 1 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: afs: Fix page leak There's a loop in afs_extend_writeback() that adds extra pages to a write we want to make to improve the efficiency of the writeback by making it larger. This loop stops, however, if we hit a page we can't write back from immediately, but it doesn't get rid of the page ref we speculatively acquired. This was caused by the removal of the cleanup loop when the code switched from using find_get_pages_contig() to xarray scanning as the latter only gets a single page at a time, not a batch. Fix this by putting the page on a ref on an early break from the loop. Unfortunately, we can't just add that page to the pagevec we're employing as we'll go through that and add those pages to the RPC call. This was found by the generic/074 test. It leaks ~4GiB of RAM each time it is run - which can be observed with "top".
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 5.13 and later | 5.14.9, 5.15 | Patch available | CNA |
- Linux VendorLinux Affected 5.13 and later Fixed in 5.14.9, 5.15 Patch available CNA
CPE configurations NVD · 4
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 5.13 to before 5.14.9 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.14.9:*:*:*:*:*:*:* | 5.14.9 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:* | 5.15 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:* | 5.15 rc2 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.13 to before 5.14.9 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.14.9:*:*:*:*:*:*:* Versions 5.14.9 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:* Versions 5.15 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:* Versions 5.15 rc2 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.14.9, 5.15
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 9 | Affected | No fix planned: Will not fix |
Not affected: 3 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
Timeline
- 2026-10-02 Threatist record created from CVE-2021-47365
- 2026-10-03 Alias added: GHSA-95jq-x6q9-c9cq
References
More Linux Kernel vulnerabilities
- TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
- TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2021-47365 · CVE Program
- CVE-2021-47365 · NVD
- FIRST EPSS
- GHSA-95jq-x6q9-c9cq · GitHub Advisory Database · CC BY 4.0
- CVE-2021-47365 · Red Hat security data · CC BY 4.0
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