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CVE-2024-42271· NVD / CVE Program· CNA Linux

net/iucv: fix use after free in iucv_sock_close()

In the Linux kernel, the following vulnerability has been resolved: net/iucv: fix use after free in iucv_sock_close() iucv_sever_path() is called from process context and from bh context. iucv->path is used as indicator whether somebody else is taking care of severing the path (or it is already removed / never existed). This needs to be done with atomic compare and swap, otherwise there is a small window where iucv_sock_close() will try to work with a path that has already been severed and freed by iucv_callback_connrej() called by iucv_tasklet_fn(). Example: [452744.123844] Call Trace: [452744.123845] ([<0000001e87f03880>] 0x1e87f03880) [452744.123966] [<00000000d593001e>] iucv_path_sever+0x96/0x138 [452744.124330] [<000003ff801ddbca>] iucv_sever_path+0xc2/0xd0 [af_iucv] [452744.124336] [<000003ff801e01b6>] iucv_sock_close+0xa6/0x310 [af_iucv] [452744.124341] [<000003ff801e08cc>] iucv_sock_release+0x3c/0xd0 [af_iucv] [452744.124345] [<00000000d574794e>] __sock_release+0x5e/0xe8 [452744.124815] [<00000000d5747a0c>] sock_close+0x34/0x48 [452744.124820] [<00000000d5421642>] __fput+0xba/0x268 [452744.124826] [<00000000d51b382c>] task_work_run+0xbc/0xf0 [452744.124832] [<00000000d5145710>] do_notify_resume+0x88/0x90 [452744.124841] [<00000000d5978096>] system_call+0xe2/0x2c8 [452744.125319] Last Breaking-Event-Address: [452744.125321] [<00000000d5930018>] iucv_path_sever+0x90/0x138 [452744.125324] [452744.125325] Kernel panic - not syncing: Fatal exception in interrupt Note that bh_lock_sock() is not serializing the tasklet context against process context, because the check for sock_owned_by_user() and corresponding handling is missing. Ideas for a future clean-up patch: A) Correct usage of bh_lock_sock() in tasklet context, as described in Re-enqueue, if needed. This may require adding return values to the tasklet functions and thus changes to all users of iucv. B) Change iucv tasklet into worker and use only lock_sock() in af_iucv.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Aug 17, 2024
Updated
Aug 5, 2026
EPSS
0.2% · 13th percentile
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Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.8
CNA · Linux
7.8
agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel3.4 and later · before 4.19.320
  • linux linux kernel4.20 and later · before 5.4.282
  • linux linux kernel5.5 and later · before 5.10.224
  • linux linux kernel5.11 and later · before 5.15.165
  • linux linux kernel5.16 and later · before 6.1.104
  • linux linux kernel6.2 and later · before 6.6.45
  • linux linux kernel6.7 and later · before 6.10.4
  • linux linux kernel6.11

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 3.4affected
    • 7d316b9453523498246e9e19a659c423d4c5081e and later · before 84f40b46787ecb67c7ad08a5bb1376141fa10c01affected · git
    • 7d316b9453523498246e9e19a659c423d4c5081e and later · before 37652fbef9809411cea55ea5fa1a170e299efcd0affected · git
    • 7d316b9453523498246e9e19a659c423d4c5081e and later · before c65f72eec60a34ace031426e04e9aff8e5f04895affected · git
    • 7d316b9453523498246e9e19a659c423d4c5081e and later · before ac758e1f663fe9bc64f6b47212a2aa18697524f5affected · git
    • 7d316b9453523498246e9e19a659c423d4c5081e and later · before 8b424c9e44111c5a76f41c6b741f8d4c4179d876affected · git
    • 7d316b9453523498246e9e19a659c423d4c5081e and later · before 01437282fd3904810603f3dc98d2cac6b8b6fc84affected · git
    • 7d316b9453523498246e9e19a659c423d4c5081e and later · before 69620522c48ce8215e5eb55ffbab8cafee8f407daffected · git
    • 7d316b9453523498246e9e19a659c423d4c5081e and later · before f558120cd709682b739207b48cf7479fd9568431affected · git
    • before 3.4not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.106-16.1.106-1
Debian:13linuxbefore 6.10.4-16.10.4-1
Red Hat:rhel_eus:9.2::appstreambpftool-debuginfobefore 0:7.0.0-284.92.1.el9_20:7.0.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-64k-debug-debuginfobefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-64k-debug-develbefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-64k-debug-devel-matchedbefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-64k-debuginfobefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-64k-develbefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-64k-devel-matchedbefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-debug-debuginfobefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-debug-develbefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-debug-devel-matchedbefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-debuginfobefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-debuginfo-common-aarch64before 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-debuginfo-common-ppc64lebefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-debuginfo-common-s390xbefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-debuginfo-common-x86_64before 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-develbefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-devel-matchedbefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-tools-debuginfobefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-zfcpdump-debuginfobefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-zfcpdump-develbefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamkernel-zfcpdump-devel-matchedbefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2
Red Hat:rhel_eus:9.2::appstreamperfbefore 0:5.14.0-284.92.1.el9_20:5.14.0-284.92.1.el9_2

+53

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Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux01437282fd3904810603f3dc98d2cac6b8b6fc84Vendor (CNA)
Linux Linux37652fbef9809411cea55ea5fa1a170e299efcd0Vendor (CNA)
Linux Linux69620522c48ce8215e5eb55ffbab8cafee8f407dVendor (CNA)
Linux Linux84f40b46787ecb67c7ad08a5bb1376141fa10c01Vendor (CNA)
Linux Linux8b424c9e44111c5a76f41c6b741f8d4c4179d876Vendor (CNA)
Linux Linuxac758e1f663fe9bc64f6b47212a2aa18697524f5Vendor (CNA)
Linux Linuxc65f72eec60a34ace031426e04e9aff8e5f04895Vendor (CNA)
Linux Linuxf558120cd709682b739207b48cf7479fd9568431Vendor (CNA)
debian:linux6.1.106-1 · Debian:12Package registry (OSV)
red hat:bpftool-debuginfo0:7.0.0-284.92.1.el9_2 · Red Hat:rhel_eus:9.2::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-debuginfo0:5.14.0-284.92.1.el9_2 · Red Hat:rhel_eus:9.2::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-devel0:5.14.0-284.92.1.el9_2 · Red Hat:rhel_eus:9.2::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-devel-matched0:5.14.0-284.92.1.el9_2 · Red Hat:rhel_eus:9.2::appstreamPackage registry (OSV)
red hat:kernel-64k-debuginfo0:5.14.0-284.92.1.el9_2 · Red Hat:rhel_eus:9.2::appstreamPackage registry (OSV)
red hat:kernel-64k-devel0:5.14.0-284.92.1.el9_2 · Red Hat:rhel_eus:9.2::appstreamPackage registry (OSV)
red hat:kernel-64k-devel-matched0:5.14.0-284.92.1.el9_2 · Red Hat:rhel_eus:9.2::appstreamPackage registry (OSV)
red hat:kernel-debug-debuginfo0:5.14.0-284.92.1.el9_2 · Red Hat:rhel_eus:9.2::appstreamPackage registry (OSV)
red hat:kernel-debug-devel0:5.14.0-284.92.1.el9_2 · Red Hat:rhel_eus:9.2::appstreamPackage registry (OSV)
red hat:kernel-debug-devel-matched0:5.14.0-284.92.1.el9_2 · Red Hat:rhel_eus:9.2::appstreamPackage registry (OSV)
red hat:kernel-debuginfo0:5.14.0-284.92.1.el9_2 · Red Hat:rhel_eus:9.2::appstreamPackage registry (OSV)
red hat:kernel-debuginfo-common-aarch640:5.14.0-284.92.1.el9_2 · Red Hat:rhel_eus:9.2::appstreamPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

c
free(dev->buf);/* ... another thread is still running ... */process(dev->buf);

Fixed

c
lock(&dev->lock);free(dev->buf);dev->buf = NULL;unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

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Change log

  1. Fix✗ → ✓

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References

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