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macvlan: fix error recovery in macvlan_common_newlink() (Linux Linux)

CVE-2026-23209
HIGH 7.8

At a glance

Source
NVD
EPSS
EPSS 0.18 % · percentile 7 ()
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Modified

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Description

In the Linux kernel, the following vulnerability has been resolved: macvlan: fix error recovery in macvlan_common_newlink() valis provided a nice repro to crash the kernel: ip link add p1 type veth peer p2 ip link set address 00:00:00:00:00:20 dev p1 ip link set up dev p1 ip link set up dev p2 ip link add mv0 link p2 type macvlan mode source ip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20 ping -c1 -I p1 1.2.3.4 He also gave a very detailed analysis: <quote valis> The issue is triggered when a new macvlan link is created with MACVLAN_MODE_SOURCE mode and MACVLAN_MACADDR_ADD (or MACVLAN_MACADDR_SET) parameter, lower device already has a macvlan port and register_netdevice() called from macvlan_common_newlink() fails (e.g. because of the invalid link name). In this case macvlan_hash_add_source is called from macvlan_change_sources() / macvlan_common_newlink(): This adds a reference to vlan to the port's vlan_source_hash using macvlan_source_entry. vlan is a pointer to the priv data of the link that is being created. When register_netdevice() fails, the error is returned from macvlan_newlink() to rtnl_newlink_create(): if (ops->newlink) err = ops->newlink(dev, &params, extack); else err = register_netdevice(dev); if (err < 0) { free_netdev(dev); goto out; } and free_netdev() is called, causing a kvfree() on the struct net_device that is still referenced in the source entry attached to the lower device's macvlan port. Now all packets sent on the macvlan port with a matching source mac address will trigger a use-after-free in macvlan_forward_source(). </quote valis> With all that, my fix is to make sure we call macvlan_flush_sources() regardless of @create value whenever "goto destroy_macvlan_port;" path is taken. Many thanks to valis for following up on this issue.

Weaknesses (CWE)

References

Scores

VersionScoreVectorScored by
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HLinux
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary)
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · nvd@nist.gov (Primary)

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
Linux · Linuxaffected aa5fd0fb77486b8a6764ead8627baa14790e4280 < da5c6b8ae47e414be47e5e04def15b25d5c962dc ; affected aa5fd0fb77486b8a6764ead8627baa14790e4280 < 5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a ; affected aa5fd0fb77486b8a6764ead8627baa14790e4280 < c43d0e787cbba569ec9d11579ed370b50fab6c9c ; affected aa5fd0fb77486b8a6764ead8627baa14790e4280 < 11ba9f0dc865136174cb98834280fb21bbc950c7 ; affected aa5fd0fb77486b8a6764ead8627baa14790e4280 < 986967a162142710076782d5b93daab93a892980 ; affected aa5fd0fb77486b8a6764ead8627baa14790e4280 < cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66
Linux · Linuxaffected 4.9 ; unaffected 0 < 4.9 ; unaffected 5.10.250 ≤ 5.10.* ; unaffected 5.15.200 ≤ 5.15.* ; unaffected 6.1.163 ≤ 6.1.* ; unaffected 6.6.124 ≤ 6.6.*

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD