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NVD / CVE Program· CNA Linux

CVE-2021-47468: isdn: mISDN: Fix sleeping function called from invalid context

MediumCVSS 5.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.17% (FIRST EPSS).
  • 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.
  • Fixed version: Linux Linux 37e4f57b22cc5ebb3f80cf0f74fdeb487f082367, 4054b869dc263228d30a4755800b78f0f2ba0c89, 6510e80a0b81b5d814e3aea6297ba42f5e76f73c.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 37e4f57b22cc5ebb3f80cf0f74fdeb487f082367, 4054b869dc263228d30a4755800b78f0f2ba0c89, 6510e80a0b81b5d814e3aea6297ba42f5e76f73c or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: isdn: mISDN: Fix sleeping function called from invalid context The driver can call card->isac.release() function from an atomic context. Fix this by calling this function after releasing the lock. The following log reveals it: [ 44.168226 ] BUG: sleeping function called from invalid context at kernel/workqueue.c:3018 [ 44.168941 ] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 5475, name: modprobe [ 44.169574 ] INFO: lockdep is turned off. [ 44.169899 ] irq event stamp: 0 [ 44.170160 ] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [ 44.170627 ] hardirqs last disabled at (0): [<ffffffff814209ed>] copy_process+0x132d/0x3e00 [ 44.171240 ] softirqs last enabled at (0): [<ffffffff81420a1a>] copy_process+0x135a/0x3e00 [ 44.171852 ] softirqs last disabled at (0): [<0000000000000000>] 0x0 [ 44.172318 ] Preemption disabled at: [ 44.172320 ] [<ffffffffa009b0a9>] nj_release+0x69/0x500 [netjet] [ 44.174441 ] Call Trace: [ 44.174630 ] dump_stack_lvl+0xa8/0xd1 [ 44.174912 ] dump_stack+0x15/0x17 [ 44.175166 ] ___might_sleep+0x3a2/0x510 [ 44.175459 ] ? nj_release+0x69/0x500 [netjet] [ 44.175791 ] __might_sleep+0x82/0xe0 [ 44.176063 ] ? start_flush_work+0x20/0x7b0 [ 44.176375 ] start_flush_work+0x33/0x7b0 [ 44.176672 ] ? trace_irq_enable_rcuidle+0x85/0x170 [ 44.177034 ] ? kasan_quarantine_put+0xaa/0x1f0 [ 44.177372 ] ? kasan_quarantine_put+0xaa/0x1f0 [ 44.177711 ] __flush_work+0x11a/0x1a0 [ 44.177991 ] ? flush_work+0x20/0x20 [ 44.178257 ] ? lock_release+0x13c/0x8f0 [ 44.178550 ] ? __kasan_check_write+0x14/0x20 [ 44.178872 ] ? do_raw_spin_lock+0x148/0x360 [ 44.179187 ] ? read_lock_is_recursive+0x20/0x20 [ 44.179530 ] ? __kasan_check_read+0x11/0x20 [ 44.179846 ] ? do_raw_spin_unlock+0x55/0x900 [ 44.180168 ] ? ____kasan_slab_free+0x116/0x140 [ 44.180505 ] ? _raw_spin_unlock_irqrestore+0x41/0x60 [ 44.180878 ] ? skb_queue_purge+0x1a3/0x1c0 [ 44.181189 ] ? kfree+0x13e/0x290 [ 44.181438 ] flush_work+0x17/0x20 [ 44.181695 ] mISDN_freedchannel+0xe8/0x100 [ 44.182006 ] isac_release+0x210/0x260 [mISDNipac] [ 44.182366 ] nj_release+0xf6/0x500 [netjet] [ 44.182685 ] nj_remove+0x48/0x70 [netjet] [ 44.182989 ] pci_device_remove+0xa9/0x250

Published
May 22, 2024
Updated
Jun 17, 2026
EPSS
0.1% · 7th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

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

    • 2.6.32affected
    • a900845e56617edc005fd8f35bfd5a407aaf96c8 and later · before 6f95c97e0f9d6eb39c3f2cb45e8fa4268d1b372baffected · git
    • a900845e56617edc005fd8f35bfd5a407aaf96c8 and later · before ef269a8808cb1759245a98a7fe16fceaebad894caffected · git
    • a900845e56617edc005fd8f35bfd5a407aaf96c8 and later · before 37e4f57b22cc5ebb3f80cf0f74fdeb487f082367affected · git
    • a900845e56617edc005fd8f35bfd5a407aaf96c8 and later · before a5b34409d3fc52114c828be4adbc30744fa3258baffected · git
    • a900845e56617edc005fd8f35bfd5a407aaf96c8 and later · before 4054b869dc263228d30a4755800b78f0f2ba0c89affected · git
    • a900845e56617edc005fd8f35bfd5a407aaf96c8 and later · before 9f591cbdbed3d7822b2bdba89b34a6d7b434317daffected · git
    • a900845e56617edc005fd8f35bfd5a407aaf96c8 and later · before f5966ba53013149bcf94e1536644a958dd00a026affected · git
    • a900845e56617edc005fd8f35bfd5a407aaf96c8 and later · before 6510e80a0b81b5d814e3aea6297ba42f5e76f73caffected · git
    • before 2.6.32not affected · semver
Affected versions · NVD (8)

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

  • linux linux kernelbefore 4.4.290
  • linux linux kernel4.5 and later · before 4.9.288
  • linux linux kernel4.10 and later · before 4.14.253
  • linux linux kernel4.15 and later · before 4.19.214
  • linux linux kernel4.20 and later · before 5.4.156
  • linux linux kernel5.5 and later · before 5.10.76
  • linux linux kernel5.11 and later · before 5.14.15
  • linux linux kernel5.15

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:8bpftoolbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernelbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-abi-stablelistsbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-corebefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-cross-headersbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-debugbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-debug-corebefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-debug-develbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-debug-modulesbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-debug-modules-extrabefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-develbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-docbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-headersbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-modulesbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-modules-extrabefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-rtbefore 4.18.0-553.16.1.rt7.357.el8_104.18.0-553.16.1.rt7.357.el8_10
AlmaLinux:8kernel-rt-corebefore 4.18.0-553.16.1.rt7.357.el8_104.18.0-553.16.1.rt7.357.el8_10
AlmaLinux:8kernel-rt-debugbefore 4.18.0-553.16.1.rt7.357.el8_104.18.0-553.16.1.rt7.357.el8_10
AlmaLinux:8kernel-rt-debug-corebefore 4.18.0-553.16.1.rt7.357.el8_104.18.0-553.16.1.rt7.357.el8_10
AlmaLinux:8kernel-rt-debug-develbefore 4.18.0-553.16.1.rt7.357.el8_104.18.0-553.16.1.rt7.357.el8_10
AlmaLinux:8kernel-rt-debug-kvmbefore 4.18.0-553.16.1.rt7.357.el8_104.18.0-553.16.1.rt7.357.el8_10
AlmaLinux:8kernel-rt-debug-modulesbefore 4.18.0-553.16.1.rt7.357.el8_104.18.0-553.16.1.rt7.357.el8_10
AlmaLinux:8kernel-rt-debug-modules-extrabefore 4.18.0-553.16.1.rt7.357.el8_104.18.0-553.16.1.rt7.357.el8_10
AlmaLinux:8kernel-rt-develbefore 4.18.0-553.16.1.rt7.357.el8_104.18.0-553.16.1.rt7.357.el8_10

+96

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe…KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2021-47466May 22, 2024 · mm, slub: fix potential memoryleak in kmem_cache_open()
    22Monitor
  • ← EarlierCVE-2021-47467May 22, 2024 · kunit: fix reference count leak in kfree_at_end
    21Monitor
  • Later →CVE-2021-47470May 22, 2024 · mm, slub: fix potential use-after-free in slab_debugfs_fops
    31Monitor

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 Linux37e4f57b22cc5ebb3f80cf0f74fdeb487f082367Vendor (CNA)
Linux Linux4054b869dc263228d30a4755800b78f0f2ba0c89Vendor (CNA)
Linux Linux6510e80a0b81b5d814e3aea6297ba42f5e76f73cVendor (CNA)
Linux Linux6f95c97e0f9d6eb39c3f2cb45e8fa4268d1b372bVendor (CNA)
Linux Linux9f591cbdbed3d7822b2bdba89b34a6d7b434317dVendor (CNA)
Linux Linuxa5b34409d3fc52114c828be4adbc30744fa3258bVendor (CNA)
Linux Linuxef269a8808cb1759245a98a7fe16fceaebad894cVendor (CNA)
Linux Linuxf5966ba53013149bcf94e1536644a958dd00a026Vendor (CNA)
almalinux:bpftool4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-abi-stablelists4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-core4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-cross-headers4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-core4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-devel4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-modules4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-modules-extra4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-devel4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-doc4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt4.18.0-553.16.1.rt7.357.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-core4.18.0-553.16.1.rt7.357.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug4.18.0-553.16.1.rt7.357.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug-core4.18.0-553.16.1.rt7.357.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug-devel4.18.0-553.16.1.rt7.357.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug-kvm4.18.0-553.16.1.rt7.357.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug-modules4.18.0-553.16.1.rt7.357.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug-modules-extra4.18.0-553.16.1.rt7.357.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-devel4.18.0-553.16.1.rt7.357.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-kvm4.18.0-553.16.1.rt7.357.el8_10 · AlmaLinux:8Package registry (OSV)

+29

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.

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

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

Weakness class (CWE)

CWE-667 · Improper Locking

CVSS vector

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

nvd-primary

Attack context

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

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records