CVE-2022-50401

  • Published: 2025-09-18T16:15:42.353

In the Linux kernel, the following vulnerability has been resolved:

nfsd: under NFSv4.1, fix double svc_xprt_put on rpc_create failure

On error situation `clp->cl_cb_conn.cb_xprt` should not be given
a reference to the xprt otherwise both client cleanup and the
error handling path of the caller call to put it. Better to
delay handing over the reference to a later branch.

[ 72.530665] refcount_t: underflow; use-after-free.
[ 72.531933] WARNING: CPU: 0 PID: 173 at lib/refcount.c:28 refcount_warn_saturate+0xcf/0x120
[ 72.533075] Modules linked in: nfsd(OE) nfsv4(OE) nfsv3(OE) nfs(OE) lockd(OE) compat_nfs_ssc(OE) nfs_acl(OE) rpcsec_gss_krb5(OE) auth_rpcgss(OE) rpcrdma(OE) dns_resolver fscache netfs grace rdma_cm iw_cm ib_cm sunrpc(OE) mlx5_ib mlx5_core mlxfw pci_hyperv_intf ib_uverbs ib_core xt_MASQUERADE nf_conntrack_netlink nft_counter xt_addrtype nft_compat br_netfilter bridge stp llc nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip_set overlay nf_tables nfnetlink crct10dif_pclmul crc32_pclmul ghash_clmulni_intel xfs serio_raw virtio_net virtio_blk net_failover failover fuse [last unloaded: sunrpc]
[ 72.540389] CPU: 0 PID: 173 Comm: kworker/u16:5 Tainted: G OE 5.15.82-dan #1
[ 72.541511] Hardware name: Red Hat KVM/RHEL-AV, BIOS 1.16.0-3.module+el8.7.0+1084+97b81f61 04/01/2014
[ 72.542717] Workqueue: nfsd4_callbacks nfsd4_run_cb_work [nfsd]
[ 72.543575] RIP: 0010:refcount_warn_saturate+0xcf/0x120
[ 72.544299] Code: 55 00 0f 0b 5d e9 01 50 98 00 80 3d 75 9e 39 08 00 0f 85 74 ff ff ff 48 c7 c7 e8 d1 60 8e c6 05 61 9e 39 08 01 e8 f6 51 55 00 0b 5d e9 d9 4f 98 00 80 3d 4b 9e 39 08 00 0f 85 4c ff ff ff 48
[ 72.546666] RSP: 0018:ffffb3f841157cf0 EFLAGS: 00010286
[ 72.547393] RAX: 0000000000000026 RBX: ffff89ac6231d478 RCX: 0000000000000000
[ 72.548324] RDX: ffff89adb7c2c2c0 RSI: ffff89adb7c205c0 RDI: ffff89adb7c205c0
[ 72.549271] RBP: ffffb3f841157cf0 R08: 0000000000000000 R09: c0000000ffefffff
[ 72.550209] R10: 0000000000000001 R11: ffffb3f841157ad0 R12: ffff89ac6231d180
[ 72.551142] R13: ffff89ac6231d478 R14: ffff89ac40c06180 R15: ffff89ac6231d4b0
[ 72.552089] FS: 0000000000000000(0000) GS:ffff89adb7c00000(0000) knlGS:0000000000000000
[ 72.553175] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 72.553934] CR2: 0000563a310506a8 CR3: 0000000109a66000 CR4: 0000000000350ef0
[ 72.554874] Call Trace:
[ 72.555278]
[ 72.555614] svc_xprt_put+0xaf/0xe0 [sunrpc]
[ 72.556276] nfsd4_process_cb_update.isra.11+0xb7/0x410 [nfsd]
[ 72.557087] ? update_load_avg+0x82/0x610
[ 72.557652] ? cpuacct_charge+0x60/0x70
[ 72.558212] ? dequeue_entity+0xdb/0x3e0
[ 72.558765] ? queued_spin_unlock+0x9/0x20
[ 72.559358] nfsd4_run_cb_work+0xfc/0x270 [nfsd]
[ 72.560031] process_one_work+0x1df/0x390
[ 72.560600] worker_thread+0x37/0x3b0
[ 72.561644] ? process_one_work+0x390/0x390
[ 72.562247] kthread+0x12f/0x150
[ 72.562710] ? set_kthread_struct+0x50/0x50
[ 72.563309] ret_from_fork+0x22/0x30
[ 72.563818]
[ 72.564189] —[ end trace 031117b1c72ec616 ]—
[ 72.566019] list_add corruption. next->prev should be prev (ffff89ac4977e538), but was ffff89ac4763e018. (next=ffff89ac4763e018).
[ 72.567647] ————[ cut here ]————

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How to fix CVE-2022-50401

CVE-2022-50401 is a unknown severity vulnerability affecting the affected product.

Description: In the Linux kernel, the following vulnerability has been resolved: nfsd: under NFSv4.1, fix double svc_xprt_put on rpc_create failure On error situation `clp->cl_cb_conn.cb_xprt` should not be given a reference to the xprt otherwise both client cleanup and the error handling path of the caller call to put it. Better to delay handing over the reference […]

Exploit Difficulty: HARD
⏱️ Time to exploit: > 4 hours
🛠️ Required skills: Advanced security expertise
💰 Public exploits: Rare or not public

How to Fix:

1 Identify affected systems

- Check if you're running the affected product

2 Immediate actions

- Update to the latest patched version
- If patching is not immediately possible: restrict network exposure, apply least-privilege access

3 Verification

- Test the fix in a staging environment first
- Review logs for signs of exploitation
- Monitor for IOCs (Indicators of Compromise)

4 Long-term prevention

- Enable automatic security updates
- Set up vulnerability monitoring
- Review and harden security configurations

Exploit Difficulty Assessment

HARD
⏱️ Time to Exploit: > 4 hours
🛠️ Skills Required: Advanced security expertise
💰 Public Exploits: Rare or not public

Vulnerability Timeline

Sep 18, 2025
Vulnerability Published

CVE details first published to NVD database

Nov 12, 2025
Imported to Database

Added to this CVE tracking system

Detection Rules & IOCs

No specific detection rules generated for this vulnerability type.

No vendor/product data available.