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NVD / CVE Program· CNA Linux

CVE-2022-50000: netfilter: flowtable: fix stuck flows on cleanup due to pending work

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: 0.24% (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 89e135a36a9eb81412b5459df94a80995ce62eef, 8fbdec08dbf7d7ab8e35bdc65eb4394bc82d1e26, 9afb4b27349a499483ae0134282cefd0c90f480f.
  • Severity is disputed: the assigning authority (CNA) scores it 7.8, NVD 5.5.

Low priority for now. Upgrade to Linux Linux 89e135a36a9eb81412b5459df94a80995ce62eef, 8fbdec08dbf7d7ab8e35bdc65eb4394bc82d1e26, 9afb4b27349a499483ae0134282cefd0c90f480f 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: netfilter: flowtable: fix stuck flows on cleanup due to pending work To clear the flow table on flow table free, the following sequence normally happens in order: 1) gc_step work is stopped to disable any further stats/del requests. 2) All flow table entries are set to teardown state. 3) Run gc_step which will queue HW del work for each flow table entry. 4) Waiting for the above del work to finish (flush). 5) Run gc_step again, deleting all entries from the flow table. 6) Flow table is freed. But if a flow table entry already has pending HW stats or HW add work step 3 will not queue HW del work (it will be skipped), step 4 will wait for the pending add/stats to finish, and step 5 will queue HW del work which might execute after freeing of the flow table. To fix the above, this patch flushes the pending work, then it sets the teardown flag to all flows in the flowtable and it forces a garbage collector run to queue work to remove the flows from hardware, then it flushes this new pending work and (finally) it forces another garbage collector run to remove the entry from the software flowtable. Stack trace: [47773.882335] BUG: KASAN: use-after-free in down_read+0x99/0x460 [47773.883634] Write of size 8 at addr ffff888103b45aa8 by task kworker/u20:6/543704 [47773.885634] CPU: 3 PID: 543704 Comm: kworker/u20:6 Not tainted 5.12.0-rc7+ #2 [47773.886745] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009) [47773.888438] Workqueue: nf_ft_offload_del flow_offload_work_handler [nf_flow_table] [47773.889727] Call Trace: [47773.890214] dump_stack+0xbb/0x107 [47773.890818] print_address_description.constprop.0+0x18/0x140 [47773.892990] kasan_report.cold+0x7c/0xd8 [47773.894459] kasan_check_range+0x145/0x1a0 [47773.895174] down_read+0x99/0x460 [47773.899706] nf_flow_offload_tuple+0x24f/0x3c0 [nf_flow_table] [47773.907137] flow_offload_work_handler+0x72d/0xbe0 [nf_flow_table] [47773.913372] process_one_work+0x8ac/0x14e0 [47773.921325] [47773.921325] Allocated by task 592159: [47773.922031] kasan_save_stack+0x1b/0x40 [47773.922730] __kasan_kmalloc+0x7a/0x90 [47773.923411] tcf_ct_flow_table_get+0x3cb/0x1230 [act_ct] [47773.924363] tcf_ct_init+0x71c/0x1156 [act_ct] [47773.925207] tcf_action_init_1+0x45b/0x700 [47773.925987] tcf_action_init+0x453/0x6b0 [47773.926692] tcf_exts_validate+0x3d0/0x600 [47773.927419] fl_change+0x757/0x4a51 [cls_flower] [47773.928227] tc_new_tfilter+0x89a/0x2070 [47773.936652] [47773.936652] Freed by task 543704: [47773.937303] kasan_save_stack+0x1b/0x40 [47773.938039] kasan_set_track+0x1c/0x30 [47773.938731] kasan_set_free_info+0x20/0x30 [47773.939467] __kasan_slab_free+0xe7/0x120 [47773.940194] slab_free_freelist_hook+0x86/0x190 [47773.941038] kfree+0xce/0x3a0 [47773.941644] tcf_ct_flow_table_cleanup_work Original patch description and stack trace by Paul Blakey.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jun 18, 2025
Updated
Aug 5, 2026
EPSS
0.2% · 16th 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 · 0.2%

CNA vs NVD score

NVD
5.5
CNA · Linux
7.8
2.3 point gap

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

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

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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

Affected versions

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

  • linux linux kernel5.5 and later · before 5.15.64
  • linux linux kernel5.16 and later · before 5.19.6
  • linux linux kernel6.0

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

    • 5.5affected
    • c29f74e0df7a02b8303bcdce93a7c0132d62577a and later · before 8fbdec08dbf7d7ab8e35bdc65eb4394bc82d1e26affected · git
    • c29f74e0df7a02b8303bcdce93a7c0132d62577a and later · before 89e135a36a9eb81412b5459df94a80995ce62eefaffected · git
    • c29f74e0df7a02b8303bcdce93a7c0132d62577a and later · before 9afb4b27349a499483ae0134282cefd0c90f480faffected · git
    • before 5.5not affected · semver
    • 5.15.64 and later · up to and including 5.15.*not affected · semver
    • 5.19.6 and later · up to and including 5.19.*not affected · semver
    • 6.0 and laternot affected · original_commit_for_fix

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.19.6-15.19.6-1
Red Hat:enterprise_linux:8::baseosbpftoolbefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseosbpftool-debuginfobefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernelbefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-abi-stablelistsbefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-corebefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-debugbefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-debug-corebefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-debug-debuginfobefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-debug-develbefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-debug-modulesbefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-debug-modules-extrabefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-debuginfobefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-debuginfo-common-aarch64before 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-debuginfo-common-ppc64lebefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-debuginfo-common-s390xbefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-debuginfo-common-x86_64before 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-develbefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-docbefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-modulesbefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-modules-extrabefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-toolsbefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-tools-debuginfobefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7
Red Hat:enterprise_linux:8::baseoskernel-tools-libsbefore 0:4.18.0-425.10.1.el8_70:4.18.0-425.10.1.el8_7

+71

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-2022-49998Jun 18, 2025 · rxrpc: Fix locking in rxrpc's sendmsg
    22Monitor
  • ← EarlierCVE-2022-49999Jun 18, 2025 · btrfs: fix space cache corruption and potential double allocations
    31Monitor
  • Later →CVE-2022-50001Jun 18, 2025 · netfilter: nft_tproxy: restrict to prerouting hook
    22Monitor

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 Linux89e135a36a9eb81412b5459df94a80995ce62eefVendor (CNA)
Linux Linux8fbdec08dbf7d7ab8e35bdc65eb4394bc82d1e26Vendor (CNA)
Linux Linux9afb4b27349a499483ae0134282cefd0c90f480fVendor (CNA)
debian:linux5.19.6-1 · Debian:12Package registry (OSV)
red hat:bpftool0:4.18.0-425.10.1.el8_7 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:bpftool-debuginfo0:4.18.0-425.10.1.el8_7 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel0:4.18.0-425.10.1.el8_7 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-abi-stablelists0:4.18.0-425.10.1.el8_7 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-core0:4.18.0-425.10.1.el8_7 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug0:4.18.0-425.10.1.el8_7 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-core0:4.18.0-425.10.1.el8_7 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-debuginfo0:4.18.0-425.10.1.el8_7 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-devel0:4.18.0-425.10.1.el8_7 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-modules0:4.18.0-425.10.1.el8_7 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-modules-extra0:4.18.0-425.10.1.el8_7 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debuginfo0:4.18.0-425.10.1.el8_7 · Red Hat:enterprise_linux:8::baseosPackage 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.

No history yet (it accumulates with the daily EPSS job).

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.

Credits

All researchers

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
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-416 · Use After Free

CVSS vector

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

The bug in code

The whole CWE-416 class

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.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

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

All records