CVE-2025-39688 [Medium] | Security Vulnerability in Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: nfsd: allow SC_STATUS_FREEABLE when searching via nfs4_lookup_stateid() The pynfs DELEG8 test fails when run against nfsd. It acquires a delegation and then lets the lease time out. It then tries to use the deleg stateid and expects to see NFS4ERR_DELEG_REVOKED, but it gets bad NFS4ERR_BAD_STATEID instead. When a delegation is revoked, it's initially marked with SC_STATUS_REVOKED, or SC_STATUS_ADMIN_REVOKED and later, it's marked with the SC_STATUS_FREEABLE flag, which denotes that it is waiting for s FREE_STATEID call. nfs4_lookup_stateid() accepts a statusmask that includes the status flags that a found stateid is allowed to have. Currently, that mask never includes SC_STATUS_FREEABLE, which means that revoked delegations are (almost) never found. Add SC_STATUS_FREEABLE to the always-allowed status flags, and remove it from nfsd4_delegreturn() since it's now always implied.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.02%	0.20%	+0.18%
2	2026-05-27	0.07%	0.02%	-0.04%
3	2026-02-12	—	0.07%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.02%

0.20%

+0.18%

2026-05-27

0.07%

0.02%

-0.04%

2026-02-12

—

0.07%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.5	3.1	MEDIUM	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	1.8	3.6	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

5.5

3.1

MEDIUM

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

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L): A normal user session is enough; they don’t have to be admin.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

1.8

3.6

[email protected]

OS Trackers for CVE-2025-39688

vendor	priority	summary	link
`debian`	unimportant	CVE-2025-39688 unimportant priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2025-39688
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2025-39688
`suse`	medium	CVE-2025-39688 severity moderate: SUSE including 52 source package names (cluster-md-kmp-default, dlm-kmp-default, …), 267 product×package rows across 45 product lines (SLES-LTSS-TERADATA 15 SP2, SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS, … (45 product lines)): Known Not Affected 241, Fixed 26.	https://www.suse.com/security/cve/CVE-2025-39688/
`ubuntu`	medium	CVE-2025-39688 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1550 status rows across 10 suites (bionic, focal, jammy, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1144, ignored 147, not-affected 142, released 115, needs-triage 2.	https://ubuntu.com/security/CVE-2025-39688

Affected software / configurations for CVE-2025-39688

Vendor	Product	Version	Raw CPE
linux	linux_kernel	>= 6.11.6, < 6.12	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.12.1, < 6.12.23	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.13, < 6.13.11	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.14, < 6.14.2	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	6.12	cpe:2.3:o:linux:linux_kernel:6.12:-::::::
linux	linux_kernel	6.12	cpe:2.3:o:linux:linux_kernel:6.12:rc5::::::
linux	linux_kernel	6.12	cpe:2.3:o:linux:linux_kernel:6.12:rc6::::::
linux	linux_kernel	6.12	cpe:2.3:o:linux:linux_kernel:6.12:rc7::::::

References for CVE-2025-39688

URL	Tags
https://git.kernel.org/stable/c/52e209203c35a4fbff8af23cd3613efe5df40102	Patch
https://git.kernel.org/stable/c/5bcb44e650bc4ec7eac23df90c5e011a77fa2beb	Patch
https://git.kernel.org/stable/c/d1bc15b147d35b4cb7ca99a9a7d79d41ca342c13	Patch
https://git.kernel.org/stable/c/dc6f3295905d7185e71091870119a8c11c3808cc	Patch

URL

CVE-2025-39688 | nfsd: allow SC_STATUS_FREEABLE when searching via nfs4_lookup_stateid()

Exploit prediction scoring system (EPSS) score for CVE-2025-39688

Common vulnerability scoring system (CVSS) metrics for CVE-2025-39688

Weakness enumeration for CVE-2025-39688

OS Trackers for CVE-2025-39688

Affected software / configurations for CVE-2025-39688

References for CVE-2025-39688