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CVE-2025-21925

llc: do not use skb_get() before dev_queue_xmit()

CVSS score

5.5

EPSS probability

%0.2

Risk score

0.0

Published

1 y ago

OverviewPublic Exploits (0)NewsroomVulnerability Timeline
Official patch verified

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Vulnerability description

DayBreach CVE AI Research

CVE-2025-21925 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

In the Linux kernel, the following vulnerability has been resolved: llc: do not use skb_get() before dev_queue_xmit() syzbot is able to crash hosts [1], using llc and devices not supporting IFF_TX_SKB_SHARING. In this case, e1000 driver calls eth_skb_pad(), while the skb is shared. Simply replace skb_get() by skb_clone() in net/llc/llc_s_ac.c Note that e1000 driver might have an issue with pktgen, because it does not clear IFF_TX_SKB_SHARING, this is an orthogonal change. We need to audit other skb_get() uses in net/llc. [1] kernel BUG at net/core/skbuff.c:2178 ! Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI CPU: 0 UID: 0 PID: 16371 Comm: syz.2.2764 Not tainted 6.14.0-rc4-syzkaller-00052-gac9c34d1e45a #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:pskb_expand_head+0x6ce/0x1240 net/core/skbuff.c:2178 Call Trace: <TASK> __skb_pad+0x18a/0x610 net/core/skbuff.c:2466 __skb_put_padto include/linux/skbuff.h:3843 [inline] skb_put_padto include/linux/skbuff.h:3862 [inline] eth_skb_pad include/linux/etherdevice.h:656 [inline] e1000_xmit_frame+0x2d99/0x5800 drivers/net/ethernet/intel/e1000/e1000_main.c:3128 __netdev_start_xmit include/linux/netdevice.h:5151 [inline] netdev_start_xmit include/linux/netdevice.h:5160 [inline] xmit_one net/core/dev.c:3806 [inline] dev_hard_start_xmit+0x9a/0x7b0 net/core/dev.c:3822 sch_direct_xmit+0x1ae/0xc30 net/sched/sch_generic.c:343 __dev_xmit_skb net/core/dev.c:4045 [inline] __dev_queue_xmit+0x13d4/0x43e0 net/core/dev.c:4621 dev_queue_xmit include/linux/netdevice.h:3313 [inline] llc_sap_action_send_test_c+0x268/0x320 net/llc/llc_s_ac.c:144 llc_exec_sap_trans_actions net/llc/llc_sap.c:153 [inline] llc_sap_next_state net/llc/llc_sap.c:182 [inline] llc_sap_state_process+0x239/0x510 net/llc/llc_sap.c:209 llc_ui_sendmsg+0xd0d/0x14e0 net/llc/af_llc.c:993 sock_sendmsg_nosec net/socket.c:718 [inline]

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2025-21925 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1linuxLinux View
2linuxLinux View
3linuxlinux kernel View
4linuxlinux kernel View
5linuxlinux kernel View
6linuxlinux kernel View
7linuxlinux kernel View
8linuxlinux kernel View
9linuxlinux kernel View
10linuxlinux kernel View
11linuxlinux kernel View
Total affected vendors: 1|Products: 11

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
5.5CVSS V31MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HNVD

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

8 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

nvd

NVD tarafından Patch olarak etiketlenmiş referans

Open source
nvd

NVD tarafından Patch olarak etiketlenmiş referans

Open source
nvd

NVD tarafından Patch olarak etiketlenmiş referans

Open source
nvd

NVD tarafından Patch olarak etiketlenmiş referans

Open source
nvd

NVD tarafından Patch olarak etiketlenmiş referans

Open source
nvd

NVD tarafından Patch olarak etiketlenmiş referans

Open source
nvd

NVD tarafından Patch olarak etiketlenmiş referans

Open source
nvd

NVD tarafından Patch olarak etiketlenmiş referans

Open source
Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Apply the official update named in the evidence only to the matching product and version.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2025-21925 is associated with the following CWEs:

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')CWE-20: Improper Input Validation

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2025-21925 weaknesses.

CAPEC-66: SQL InjectionCAPEC-126: Path TraversalCAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureYerel erişim
PermissionsLow
UserGerekmiyor

Official Sources and Advisories

https://git.kernel.org/stable/c/cd1c44327bbbd50fc24f2b38892f5f328b784d0fvendor-advisoryhttps://git.kernel.org/stable/c/13f3f872627f0f27c31245524fc11367756240advendor-advisoryhttps://git.kernel.org/stable/c/9b6f083db141ece0024be01526aa05aa978811cbvendor-advisoryhttps://git.kernel.org/stable/c/17f86e25431ebc15aa9245ff156414fdad47822dvendor-advisoryhttps://git.kernel.org/stable/c/416e8b4c20c6398044e93008deefd563289f477dvendor-advisoryhttps://git.kernel.org/stable/c/0f764208dc24ea043c3e20194d32aebf94f8459cvendor-advisoryhttps://git.kernel.org/stable/c/056e8a46d79e22983bae4267e0d9c52927076f46vendor-advisoryhttps://git.kernel.org/stable/c/64e6a754d33d31aa844b3ee66fb93ac84ca1565evendor-advisoryhttps://lists.debian.org/debian-lts-announce/2025/05/msg00030.htmlnvdhttps://lists.debian.org/debian-lts-announce/2025/05/msg00045.htmlnvd

CVSS Vector Radar Chart

5.5 / 10
Attack VectorLocalComplexityLowPrivilegesLowUser Interact.NoneConfidentialityLowIntegrityNoneAvailabilityHigh

Vulnerability Scoring Details

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack VectorLocal
Attack ComplexityLow
Privileges RequiredLow privileges
User InteractionNone required
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)None
Availability (Erişilebilirlik)High

Yama doğrulandı

8 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

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