UBUNTU-CVE-2025-21646
In the Linux kernel, the following vulnerability has been resolved: afs: Fix the maximum cell name length The kafs filesystem limits the maximum length of a cell to 256 bytes, but a problem occurs if someone actually does that: kafs tries to create a directory under /proc/net/afs/ with the name of the cell, but that fails with a warning: WARNING: CPU: 0 PID: 9 at fs/proc/generic.c:405 because procfs limits the maximum filename length to 255. However, the DNS limits the maximum lookup length and, by extension, the maximum cell name, to 255 less two (length count and trailing NUL). Fix this by limiting the maximum acceptable cellname length to 253. This also allows us to be sure we can create the "/afs/.<cell>/" mountpoint too. Further, split the YFS VL record cell name maximum to be the 256 allowed by the protocol and ignore the record retrieved by YFSVL.GetCellName if it exceeds 253.
02 / AFFECTED SOFTWARE
Affected packages
11 explicit affected versions
43 explicit affected versions
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12 explicit affected versions
19 explicit affected versions
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23 explicit affected versions
54 explicit affected versions
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61 explicit affected versions
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18 explicit affected versions
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35 explicit affected versions
21 explicit affected versions
19 explicit affected versions
18 explicit affected versions
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64 explicit affected versions
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13 explicit affected versions
4 explicit affected versions
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28 explicit affected versions
1 explicit affected versions
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2 explicit affected versions
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1 explicit affected versions
52 explicit affected versions
12 explicit affected versions
14 explicit affected versions
7 explicit affected versions
2 explicit affected versions
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12 explicit affected versions
18 explicit affected versions
15 explicit affected versions
15 explicit affected versions
10 explicit affected versions
10 explicit affected versions
37 explicit affected versions
2 explicit affected versions
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10 explicit affected versions
26 explicit affected versions
13 explicit affected versions
12 explicit affected versions
29 explicit affected versions
13 explicit affected versions
66 explicit affected versions
17 explicit affected versions
18 explicit affected versions
61 explicit affected versions
24 explicit affected versions
33 explicit affected versions
23 explicit affected versions
10 explicit affected versions
1 explicit affected versions
11 explicit affected versions
12 explicit affected versions
7 explicit affected versions
12 explicit affected versions
52 explicit affected versions
46 explicit affected versions
62 explicit affected versions
10 explicit affected versions
26 explicit affected versions
22 explicit affected versions
1 explicit affected versions
13 explicit affected versions
23 explicit affected versions
13 explicit affected versions
23 explicit affected versions
16 explicit affected versions
63 explicit affected versions
26 explicit affected versions
53 explicit affected versions
3 explicit affected versions
1 explicit affected versions
2 explicit affected versions
51 explicit affected versions
9 explicit affected versions
20 explicit affected versions
12 explicit affected versions
49 explicit affected versions
27 explicit affected versions
36 explicit affected versions
19 explicit affected versions
8 explicit affected versions
26 explicit affected versions
5 explicit affected versions
8 explicit affected versions
10 explicit affected versions
22 explicit affected versions
13 explicit affected versions
13 explicit affected versions
7 explicit affected versions
2 explicit affected versions
54 explicit affected versions
10 explicit affected versions
12 explicit affected versions
15 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
13 explicit affected versions
26 explicit affected versions
45 explicit affected versions
37 explicit affected versions
27 explicit affected versions
14 explicit affected versions
38 explicit affected versions
53 explicit affected versions
9 explicit affected versions
51 explicit affected versions
11 explicit affected versions
17 explicit affected versions
7 explicit affected versions
62 explicit affected versions
7 explicit affected versions
33 explicit affected versions
4 explicit affected versions
1 explicit affected versions
1 explicit affected versions
1 explicit affected versions
60 explicit affected versions
13 explicit affected versions
43 explicit affected versions
10 explicit affected versions
8 explicit affected versions
21 explicit affected versions
14 explicit affected versions
4 explicit affected versions
78 explicit affected versions
11 explicit affected versions
1 explicit affected versions
16 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: afs: Fix the maximum cell name length The kafs filesystem limits the maximum length of a cell to 256 bytes, but a problem occurs if someone actually does that: kafs tries to create a directory under /proc/net/afs/ with the name of the cell, but that fails with a warning: WARNING: CPU: 0 PID: 9 at fs/proc/generic.c:405 because procfs limits the maximum filename length to 255. However, the DNS limits the maximum lookup length and, by extension, the maximum cell name, to 255 less two (length count and trailing NUL). Fix this by limiting the maximum acceptable cellname length to 253. This also allows us to be sure we can create the "/afs/.<cell>/" mountpoint too. Further, split the YFS VL record cell name maximum to be the 256 allowed by the protocol and ignore the record retrieved by YFSVL.GetCellName if it exceeds 253.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/8fd56ad6e7c90ac2bddb0741c6b248c8c5d56ac8
- https://git.kernel.org/stable/c/7673030efe0f8ca1056d3849d61784c6caa052af
- https://git.kernel.org/stable/c/7922b1f058fe24a93730511dd0ae2e1630920096
- https://git.kernel.org/stable/c/8fd56ad6e7c90ac2bddb0741c6b248c8c5d56ac8
- https://git.kernel.org/stable/c/aabe47cf5ac5e1db2ae0635f189d836f67024904
- https://ubuntu.com/security/CVE-2025-21646
- https://ubuntu.com/security/notices/USN-7379-1
- https://ubuntu.com/security/notices/USN-7379-2
- https://ubuntu.com/security/notices/USN-7380-1
- https://ubuntu.com/security/notices/USN-7381-1
- https://ubuntu.com/security/notices/USN-7382-1
- https://ubuntu.com/security/notices/USN-7387-1
- https://ubuntu.com/security/notices/USN-7387-2
- https://ubuntu.com/security/notices/USN-7387-3
- https://ubuntu.com/security/notices/USN-7388-1
- https://ubuntu.com/security/notices/USN-7389-1
- https://ubuntu.com/security/notices/USN-7390-1
- https://ubuntu.com/security/notices/USN-7407-1
- https://ubuntu.com/security/notices/USN-7421-1
- https://ubuntu.com/security/notices/USN-7458-1
- https://ubuntu.com/security/notices/USN-7459-1
- https://ubuntu.com/security/notices/USN-7459-2
- https://ubuntu.com/security/notices/USN-7513-1
- https://ubuntu.com/security/notices/USN-7513-2
- https://ubuntu.com/security/notices/USN-7513-3
- https://ubuntu.com/security/notices/USN-7513-4
- https://ubuntu.com/security/notices/USN-7513-5
- https://ubuntu.com/security/notices/USN-7514-1
- https://ubuntu.com/security/notices/USN-7515-1
- https://ubuntu.com/security/notices/USN-7515-2
- https://ubuntu.com/security/notices/USN-7522-1
- https://ubuntu.com/security/notices/USN-7523-1
- https://ubuntu.com/security/notices/USN-7524-1
- https://www.cve.org/CVERecord?id=CVE-2025-21646