How severe is CVE-2024-49947?

CVE-2024-49947 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2024-49947 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2024-49947?

CVE-2024-49947 primarily affects Linux Linux Kernel. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2024-49947?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2024-49947 have an EU (EUVD) identifier?

Yes. CVE-2024-49947 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-43628.

When was CVE-2024-49947 published?

CVE-2024-49947 was published on 2024-10-21 and last updated on 2026-06-17.

CVE-2024-49947

CVE-2024-49947 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
EPSS exploit prediction: 0% (14th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2024-43628
Affected product: Linux Linux Kernel
Published: 2024-10-21
Last modified: 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: net: test for not too small csum_start in virtio_net_hdr_to_skb() syzbot was able to trigger this warning [1], after injecting a malicious packet through af_packet, setting skb->csum_start and thus the transport header to an incorrect value. We can at least make sure the transport header is after the end of the network header (with a estimated minimal size). [1] [ 67.873027] skb len=4096 headroom=16 headlen=14 tailroom=0 mac=(-1,-1) mac_len=0 net=(16,-6) trans=10 shinfo(txflags=0 nr_frags=1 gso(size=0 type=0 segs=0)) csum(0xa start=10 offset=0 ip_summed=3 complete_sw=0 valid=0 level=0) hash(0x0 sw=0 l4=0) proto=0x0800 pkttype=0 iif=0 priority=0x0 mark=0x0 alloc_cpu=10 vlan_all=0x0 encapsulation=0 inner(proto=0x0000, mac=0, net=0, trans=0) [ 67.877172] dev name=veth0_vlan feat=0x000061164fdd09e9 [ 67.877764] sk family=17 type=3 proto=0 [ 67.878279] skb linear: 00000000: 00 00 10 00 00 00 00 00 0f 00 00 00 08 00 [ 67.879128] skb frag: 00000000: 0e 00 07 00 00 00 28 00 08 80 1c 00 04 00 00 02 [ 67.879877] skb frag: 00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.880647] skb frag: 00000020: 00 00 02 00 00 00 08 00 1b 00 00 00 00 00 00 00 [ 67.881156] skb frag: 00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.881753] skb frag: 00000040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.882173] skb frag: 00000050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.882790] skb frag: 00000060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.883171] skb frag: 00000070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.883733] skb frag: 00000080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.884206] skb frag: 00000090: 00 00 00 00 00 00 00 00 00 00 69 70 76 6c 61 6e [ 67.884704] skb frag: 000000a0: 31 00 00 00 00 00 00 00 00 00 2b 00 00 00 00 00 [ 67.885139] skb frag: 000000b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.885677] skb frag: 000000c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.886042] skb frag: 000000d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.886408] skb frag: 000000e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.887020] skb frag: 000000f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.887384] skb frag: 00000100: 00 00 [ 67.887878] ------------[ cut here ]------------ [ 67.887908] offset (-6) >= skb_headlen() (14) [ 67.888445] WARNING: CPU: 10 PID: 2088 at net/core/dev.c:3332 skb_checksum_help (net/core/dev.c:3332 (discriminator 2)) [ 67.889353] Modules linked in: macsec macvtap macvlan hsr wireguard curve25519_x86_64 libcurve25519_generic libchacha20poly1305 chacha_x86_64 libchacha poly1305_x86_64 dummy bridge sr_mod cdrom evdev pcspkr i2c_piix4 9pnet_virtio 9p 9pnet netfs [ 67.890111] CPU: 10 UID: 0 PID: 2088 Comm: b363492833 Not tainted 6.11.0-virtme #1011 [ 67.890183] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 67.890309] RIP: 0010:skb_checksum_help (net/core/dev.c:3332 (discriminator 2)) [ 67.891043] Call Trace: [ 67.891173] <TASK> [ 67.891274] ? __warn (kernel/panic.c:741) [ 67.891320] ? skb_checksum_help (net/core/dev.c:3332 (discriminator 2)) [ 67.891333] ? report_bug (lib/bug.c:180 lib/bug.c:219) [ 67.891348] ? handle_bug (arch/x86/kernel/traps.c:239) [ 67.891363] ? exc_invalid_op (arch/x86/kernel/traps.c:260 (discriminator 1)) [ 67.891372] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:621) [ 67.891388] ? skb_checksum_help (net/core/dev.c:3332 (discriminator 2)) [ 67.891399] ? skb_checksum_help (net/core/dev.c:3332 (discriminator 2)) [ 67.891416] ip_do_fragment (net/ipv4/ip_output.c:777 (discriminator 1)) [ 67.891448] ? __ip_local_out (./include/linux/skbuff.h:1146 ./include/net/l3mdev.h:196 ./include/net/l3mdev.h:213 ne ---truncated---

Frequently asked questions

What is CVE-2024-49947?: In the Linux kernel, the following vulnerability has been resolved: net: test for not too small csum_start in virtio_net_hdr_to_skb() syzbot was able to trigger this warning [1], after injecting a malicious packet through af_packet, setting skb->csum_start and thus the transport header to an incorrect value. We can at least make sure the transport header is after the end of the network header (with a estimated minimal size). [1] [ 67.873027] skb len=4096 headroom=16 headlen=14 tailroom=0 mac=(-1,-1) mac_len=0 net=(16,-6) trans=10 shinfo(txflags=0 nr_frags=1 gso(size=0 type=0 segs=0)) csum(0xa start=10 offset=0 ip_summed=3 complete_sw=0 valid=0 level=0) hash(0x0 sw=0 l4=0) proto=0x0800 pkttype=0 iif=0 priority=0x0 mark=0x0 alloc_cpu=10 vlan_all=0x0 encapsulation=0 inner(proto=0x0000, mac=0, net=0, trans=0) [ 67.877172] dev name=veth0_vlan feat=0x000061164fdd09e9 [ 67.877764] sk family=17 type=3 proto=0 [ 67.878279] skb linear: 00000000: 00 00 10 00 00 00 00 00 0f 00 00 00 08 00 [ 67.879128] skb frag: 00000000: 0e 00 07 00 00 00 28 00 08 80 1c 00 04 00 00 02 [ 67.879877] skb frag: 00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.880647] skb frag: 00000020: 00 00 02 00 00 00 08 00 1b 00 00 00 00 00 00 00 [ 67.881156] skb frag: 00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.881753] skb frag: 00000040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.882173] skb frag: 00000050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.882790] skb frag: 00000060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.883171] skb frag: 00000070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.883733] skb frag: 00000080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.884206] skb frag: 00000090: 00 00 00 00 00 00 00 00 00 00 69 70 76 6c 61 6e [ 67.884704] skb frag: 000000a0: 31 00 00 00 00 00 00 00 00 00 2b 00 00 00 00 00 [ 67.885139] skb frag: 000000b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.885677] skb frag: 000000c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.886042] skb frag: 000000d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.886408] skb frag: 000000e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.887020] skb frag: 000000f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 67.887384] skb frag: 00000100: 00 00 [ 67.887878] ------------[ cut here ]------------ [ 67.887908] offset (-6) >= skb_headlen() (14) [ 67.888445] WARNING: CPU: 10 PID: 2088 at net/core/dev.c:3332 skb_checksum_help (net/core/dev.c:3332 (discriminator 2)) [ 67.889353] Modules linked in: macsec macvtap macvlan hsr wireguard curve25519_x86_64 libcurve25519_generic libchacha20poly1305 chacha_x86_64 libchacha poly1305_x86_64 dummy bridge sr_mod cdrom evdev pcspkr i2c_piix4 9pnet_virtio 9p 9pnet netfs [ 67.890111] CPU: 10 UID: 0 PID: 2088 Comm: b363492833 Not tainted 6.11.0-virtme #1011 [ 67.890183] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 67.890309] RIP: 0010:skb_checksum_help (net/core/dev.c:3332 (discriminator 2)) [ 67.891043] Call Trace: [ 67.891173] <TASK> [ 67.891274] ? __warn (kernel/panic.c:741) [ 67.891320] ? skb_checksum_help (net/core/dev.c:3332 (discriminator 2)) [ 67.891333] ? report_bug (lib/bug.c:180 lib/bug.c:219) [ 67.891348] ? handle_bug (arch/x86/kernel/traps.c:239) [ 67.891363] ? exc_invalid_op (arch/x86/kernel/traps.c:260 (discriminator 1)) [ 67.891372] ? asm_exc_invalid_op (./arch/x86/include/asm/idtentry.h:621) [ 67.891388] ? skb_checksum_help (net/core/dev.c:3332 (discriminator 2)) [ 67.891399] ? skb_checksum_help (net/core/dev.c:3332 (discriminator 2)) [ 67.891416] ip_do_fragment (net/ipv4/ip_output.c:777 (discriminator 1)) [ 67.891448] ? __ip_local_out (./include/linux/skbuff.h:1146 ./include/net/l3mdev.h:196 ./include/net/l3mdev.h:213 ne ---truncated---
How severe is CVE-2024-49947?: CVE-2024-49947 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2024-49947 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-49947?: CVE-2024-49947 primarily affects Linux Linux Kernel. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2024-49947?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-49947 have an EU (EUVD) identifier?: Yes. CVE-2024-49947 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-43628.
When was CVE-2024-49947 published?: CVE-2024-49947 was published on 2024-10-21 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.12:rc1:*:*:*:*:*:*

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