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NVD / CVE Program· CNA Linux

CVE-2021-47590: mptcp: fix deadlock in __mptcp_push_pending()

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: 0.15% (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 23311b92755ffa9087332d1bb8c71c0f6a10cc08, 3d79e3756ca90f7a6087b77b62c1d9c0801e0820.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 23311b92755ffa9087332d1bb8c71c0f6a10cc08, 3d79e3756ca90f7a6087b77b62c1d9c0801e0820 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: mptcp: fix deadlock in __mptcp_push_pending() __mptcp_push_pending() may call mptcp_flush_join_list() with subflow socket lock held. If such call hits mptcp_sockopt_sync_all() then subsequently __mptcp_sockopt_sync() could try to lock the subflow socket for itself, causing a deadlock. sysrq: Show Blocked State task:ss-server state:D stack: 0 pid: 938 ppid: 1 flags:0x00000000 Call Trace: <TASK> __schedule+0x2d6/0x10c0 ? __mod_memcg_state+0x4d/0x70 ? csum_partial+0xd/0x20 ? _raw_spin_lock_irqsave+0x26/0x50 schedule+0x4e/0xc0 __lock_sock+0x69/0x90 ? do_wait_intr_irq+0xa0/0xa0 __lock_sock_fast+0x35/0x50 mptcp_sockopt_sync_all+0x38/0xc0 __mptcp_push_pending+0x105/0x200 mptcp_sendmsg+0x466/0x490 sock_sendmsg+0x57/0x60 __sys_sendto+0xf0/0x160 ? do_wait_intr_irq+0xa0/0xa0 ? fpregs_restore_userregs+0x12/0xd0 __x64_sys_sendto+0x20/0x30 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f9ba546c2d0 RSP: 002b:00007ffdc3b762d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f9ba56c8060 RCX: 00007f9ba546c2d0 RDX: 000000000000077a RSI: 0000000000e5e180 RDI: 0000000000000234 RBP: 0000000000cc57f0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9ba56c8060 R13: 0000000000b6ba60 R14: 0000000000cc7840 R15: 41d8685b1d7901b8 </TASK> Fix the issue by using __mptcp_flush_join_list() instead of plain mptcp_flush_join_list() inside __mptcp_push_pending(), as suggested by Florian. The sockopt sync will be deferred to the workqueue.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jun 19, 2024
Updated
Jun 17, 2026
EPSS
0.1% · 4th 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.

Get told when this record changes

  • 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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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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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 kernel5.13 and later · before 5.15.11

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

    • 5.13affected
    • 1b3e7ede1365a24db1b4fd837e58a595f52fa4ad and later · before 23311b92755ffa9087332d1bb8c71c0f6a10cc08affected · git
    • 1b3e7ede1365a24db1b4fd837e58a595f52fa4ad and later · before 3d79e3756ca90f7a6087b77b62c1d9c0801e0820affected · git
    • before 5.13not affected · semver
    • 5.15.11 and later · up to and including 5.15.*not affected · semver
    • 5.16 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 5.15.15-15.15.15-1
openSUSE:Leap 15.5kernel-azurebefore 5.14.21-150500.33.63.15.14.21-150500.33.63.1
openSUSE:Leap 15.5kernel-rt_debugbefore 5.14.21-150500.13.64.15.14.21-150500.13.64.1
openSUSE:Leap 15.5kernel-source-azurebefore 5.14.21-150500.33.63.15.14.21-150500.33.63.1
openSUSE:Leap 15.5kernel-source-rtbefore 5.14.21-150500.13.64.15.14.21-150500.13.64.1
openSUSE:Leap 15.5kernel-syms-azurebefore 5.14.21-150500.33.63.15.14.21-150500.33.63.1
openSUSE:Leap 15.5kernel-syms-rtbefore 5.14.21-150500.13.64.15.14.21-150500.13.64.1
openSUSE:Leap Micro 5.5kernel-rtbefore 5.14.21-150500.13.64.15.14.21-150500.13.64.1
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5-RT_Update_18before 1-150500.11.3.11-150500.11.3.1
SUSE:Linux Enterprise Micro 5.5kernel-rtbefore 5.14.21-150500.13.64.15.14.21-150500.13.64.1
SUSE:Linux Enterprise Micro 5.5kernel-source-rtbefore 5.14.21-150500.13.64.15.14.21-150500.13.64.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP5kernel-azurebefore 5.14.21-150500.33.63.15.14.21-150500.33.63.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP5kernel-source-azurebefore 5.14.21-150500.33.63.15.14.21-150500.33.63.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP5kernel-syms-azurebefore 5.14.21-150500.33.63.15.14.21-150500.33.63.1
SUSE:Real Time Module 15 SP5kernel-rt_debugbefore 5.14.21-150500.13.64.15.14.21-150500.13.64.1
SUSE:Real Time Module 15 SP5kernel-syms-rtbefore 5.14.21-150500.13.64.15.14.21-150500.13.64.1

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-2021-47588Jun 19, 2024 · sit: do not call ipip6_dev_free() from sit_init_net()
    22Monitor
  • ← EarlierCVE-2021-47589Jun 19, 2024 · igbvf: fix double free in `igbvf_probe`
    31Monitor
  • Later →CVE-2021-47591Jun 19, 2024 · mptcp: remove tcp ulp setsockopt support
    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 Linux23311b92755ffa9087332d1bb8c71c0f6a10cc08Vendor (CNA)
Linux Linux3d79e3756ca90f7a6087b77b62c1d9c0801e0820Vendor (CNA)
debian:linux5.15.15-1 · Debian:12Package registry (OSV)
opensuse:kernel-azure5.14.21-150500.33.63.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-rt5.14.21-150500.13.64.1 · openSUSE:Leap Micro 5.5Package registry (OSV)
opensuse:kernel-rt_debug5.14.21-150500.13.64.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-source-azure5.14.21-150500.33.63.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-source-rt5.14.21-150500.13.64.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-syms-azure5.14.21-150500.33.63.1 · openSUSE:Leap 15.5Package registry (OSV)
opensuse:kernel-syms-rt5.14.21-150500.13.64.1 · openSUSE:Leap 15.5Package registry (OSV)
suse:kernel-azure5.14.21-150500.33.63.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP5Package registry (OSV)
suse:kernel-livepatch-SLE15-SP5-RT_Update_181-150500.11.3.1 · SUSE:Linux Enterprise Live Patching 15 SP5Package registry (OSV)
suse:kernel-rt5.14.21-150500.13.64.1 · SUSE:Linux Enterprise Micro 5.5Package registry (OSV)
suse:kernel-rt_debug5.14.21-150500.13.64.1 · SUSE:Real Time Module 15 SP5Package registry (OSV)
suse:kernel-source-azure5.14.21-150500.33.63.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP5Package registry (OSV)
suse:kernel-source-rt5.14.21-150500.13.64.1 · SUSE:Linux Enterprise Micro 5.5Package registry (OSV)
suse:kernel-syms-azure5.14.21-150500.33.63.1 · SUSE:Linux Enterprise Module for Public Cloud 15 SP5Package registry (OSV)
suse:kernel-syms-rt5.14.21-150500.13.64.1 · SUSE:Real Time Module 15 SP5Package 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).

National notice (Türkiye Cybersecurity Directorate / USOM)

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

All national notices →

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.

Change log

  1. Fix✗ → ✓

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

References

Show all references (1 more)

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

All records