CVE-2023-52447 — bpf: Defer the free of inner map when necessary
In the Linux kernel, the following vulnerability has been resolved: bpf: Defer the free of inner map when necessary When updating or deleting an inner map in map array or map htab, the map may still be accessed by non-sleepable program or sleepable program. However bpf_map_fd_put_ptr() decreases the ref-counter of the inner map directly through bpf_map_put(), if the ref-counter is the last one (which is true for most cases), the inner map will be freed by ops->map_free() in a kworker. But for now, most .map_free() callbacks don't use synchronize_rcu() or its variants to wait for the elapse of a RCU grace period, so after the invocation of ops->map_free completes, the bpf program which is accessing the inner map may incur use-after-free problem. Fix the free of inner map by invoking bpf_map_free_deferred() after both one RCU grace period and one tasks trace RCU grace period if the inner map has been removed from the outer map before. The deferment is accomplished by using call_rcu() or call_rcu_tasks_trace() when releasing the last ref-counter of bpf map. The newly-added rcu_head field in bpf_map shares the same storage space with work field to reduce the size of bpf_map.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.2% (30-day exploitation probability)+2
- Technical severity (medium)+3
- CISA SSVC: exploitation "poc"+5
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Linux Linux, Linux Linux Kernel).
- Apply the fixed version or the patch documented under Remediation.
- Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux | ≥ bba1dc0b55ac462d24ed1228ad49800c238cd6d7 and < 90c445799fd1dc214d7c6279c144e33a35e29ef2≥ bba1dc0b55ac462d24ed1228ad49800c238cd6d7 and < 37d98fb9c3144c0fddf7f6e99aece9927ac8dce6≥ bba1dc0b55ac462d24ed1228ad49800c238cd6d7 and < 62fca83303d608ad4fec3f7428c8685680bb01b0≥ bba1dc0b55ac462d24ed1228ad49800c238cd6d7 and < f91cd728b10c51f6d4a39957ccd56d1e802fc8ee≥ bba1dc0b55ac462d24ed1228ad49800c238cd6d7 and < bfd9b20c4862f41d4590fde11d70a5eeae53dcc5≥ bba1dc0b55ac462d24ed1228ad49800c238cd6d7 and < 876673364161da50eed6b472d746ef88242b2368version 5.9 | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Linux | Linux Kernel | ≥ 5.9.0 and < 5.10.214≥ 5.11 and < 5.15.153≥ 5.16 and < 6.1.75≥ 6.2 and < 6.6.14≥ 6.7 and < 6.7.2 | Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.8 | CVSS 3.1 | High | 1.8 | 5.9 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database |
| 7.8 | CVSS 3.1 | High | — | — | GitHub, Inc. via GitHub Security Advisories |
| 7.8 | CVSS 3.1 | High | — | — | Linux via CVE Program (cve.org) e CISA ADP |
| 6.7 | CVSS 3.1 | Medium | 0.8 | 5.9 | nvd@nist.gov via NIST National Vulnerability Database |
| 6.7 | CVSS 3.1 | Medium | 0.8 | 5.9 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database |
| 6.7 | CVSS 3.1 | Medium | — | — | CISA-ADP via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
- Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · linux/linux
- SSVC assessment updated
- Record published
- Fix documented
- Affected products added · linux/linux kernel
- CVSS changed · 6.7
- Source status changed · → Modified
- Record created in this database
- 2024
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 2× References added · Oct 14, 2026 – Oct 14, 2026
- 1× Official description updated · Oct 14, 2026 – Oct 14, 2026
References
10 on the record
- git.kernel.org/stable/c/90c445799fd1dc214d7c6279c144e33a35e29ef2
- git.kernel.org/stable/c/f91cd728b10c51f6d4a39957ccd56d1e802fc8ee
- git.kernel.org/stable/c/62fca83303d608ad4fec3f7428c8685680bb01b0
- git.kernel.org/stable/c/bfd9b20c4862f41d4590fde11d70a5eeae53dcc5
- git.kernel.org/stable/c/876673364161da50eed6b472d746ef88242b2368
- git.kernel.org/stable/c/37d98fb9c3144c0fddf7f6e99aece9927ac8dce6
- lists.debian.org/debian-lts-announce/2024/06/msg00017.html
- github.com/advisories/GHSA-wvjr-h8mr-f8gw
- nvd.nist.gov/vuln/detail/CVE-2023-52447
- cert-portal.siemens.com/productcert/html/ssa-265688.html
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 13h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 13h
- Unknown CVE-2026-98431 RDMA/uverbs: Fix mmap_lock/disassociation_lock circular dependency 1d
- Unknown CVE-2026-98430 RDMA/efa: Keep admin queues alive while IRQ is registered 1d
- Unknown CVE-2026-98429 RDMA/efa: Keep EQ resources alive while IRQ is registered 1d
- Unknown CVE-2026-98428 ALSA: usb: 6fire: Avoid embedded URBs 1d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2023-52447 is "bpf: Defer the free of inner map when necessary", rated Medium. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.7 describes technical severity. EPSS 0.25% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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