CVE-2023-52443: apparmor: avoid crash when parsed profile name is empty
Vulnerability summary
CVE-2023-52443 is a medium (CVSS 5.5) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 15.1% of scored vulnerabilities.
Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 29 · Related 30Timeline
- 22-02-2024PublishedVulnerability first disclosed.
- 11-05-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: apparmor: avoid crash when parsed profile name is empty When processing a packed profile in unpack_profile() described like "profile :ns::samba-dcerpcd /usr/lib*/samba/{,samba/}samba-dcerpcd {...}" a string ":samba-dcerpcd" is unpacked as a fully-qualified name and then passed to aa_splitn_fqname(). aa_splitn_fqname() treats ":samba-dcerpcd" as only containing a namespace. Thus it returns NULL for tmpname, meanwhile tmpns is non-NULL. Later aa_alloc_profile() crashes as the new profile name is NULL now. general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 6 PID: 1657 Comm: apparmor_parser Not tainted 6.7.0-rc2-dirty #16 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014 RIP: 0010:strlen+0x1e/0xa0 Call Trace: <TASK> ? strlen+0x1e/0xa0 aa_policy_init+0x1bb/0x230 aa_alloc_profile+0xb1/0x480 unpack_profile+0x3bc/0x4960 aa_unpack+0x309/0x15e0 aa_replace_profiles+0x213/0x33c0 policy_update+0x261/0x370 profile_replace+0x20e/0x2a0 vfs_write+0x2af/0xe00 ksys_write+0x126/0x250 do_syscall_64+0x46/0xf0 entry_SYSCALL_64_after_hwframe+0x6e/0x76 </TASK> ---[ end trace 0000000000000000 ]--- RIP: 0010:strlen+0x1e/0xa0 It seems such behaviour of aa_splitn_fqname() is expected and checked in other places where it is called (e.g. aa_remove_profiles). Well, there is an explicit comment "a ns name without a following profile is allowed" inside. AFAICS, nothing can prevent unpacked "name" to be in form like ":samba-dcerpcd" - it is passed from userspace. Deny the whole profile set replacement in such case and inform user with EPROTO and an explaining message. Found by Linux Verification Center (linuxtesting.org).
CVSS metrics
4 scores · 3 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.24%
Chance of exploitation in the next 30 days
Percentile
15%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.24% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu115 products
- linux< 4.15.0-227.239 | < 5.4.0-176.196 | < 5.15.0-102.112
- linux-allwinner-5.19All versions (No fix recorded)
- linux-aws< 4.15.0-1170.183 | < 5.4.0-1122.132 | < 5.15.0-1057.63
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ 04dc715e24d0820bf8740e1a1135ed61fe162bc8, < 9286ee97aa4803d99185768735011d0d65827c9e | ≥ 04dc715e24d0820bf8740e1a1135ed61fe162bc8, < 1d8e62b5569cc1466ceb8a7e4872cf10160a9dcf | ≥ 04dc715e24d0820bf8740e1a1135ed61fe162bc8, < 5ff00408e5029d3550ee77f62dc15f1e15c47f87 | ≥ 04dc715e24d0820bf8740e1a1135ed61fe162bc8, < 0a12db736edbb4933e4274932aeea594b5876fa4 | ≥ 04dc715e24d0820bf8740e1a1135ed61fe162bc8, < 9d4fa5fe2b1d56662afd14915a73b4d0783ffa45 | ≥ 04dc715e24d0820bf8740e1a1135ed61fe162bc8, < 5c0392fdafb0a2321311900be83ffa572bef8203 | ≥ 04dc715e24d0820bf8740e1a1135ed61fe162bc8, < 77ab09b92f16c8439a948d1af489196953dc4a0e | ≥ 04dc715e24d0820bf8740e1a1135ed61fe162bc8, < 55a8210c9e7d21ff2644809699765796d4bfb200 | 4.11
- linux_kernel< 4.19.306 | ≥ 4.20, < 5.4.268 | ≥ 5.5.0, < 5.10.209 | ≥ 5.11.0, < 5.15.148 | ≥ 5.16.0, < 6.1.75 | ≥ 6.2.0, < 6.6.14 | ≥ 6.7.0, < 6.7.2
Debian1 product
- linux< 6.1.76-1 | < 6.6.15-1
3 vendors · 118 products
