CVE-2026-98419

Published Oct 14, 2026

Description

In the Linux kernel, the following vulnerability has been resolved: drop_monitor: fix out-of-bounds write in reset_per_cpu_data() In reset_per_cpu_data(), al is computed as: al = sizeof(struct net_dm_alert_msg); al += dm_hit_limit * sizeof(struct net_dm_drop_point); al += sizeof(struct nlattr); skb = genlmsg_new(al, GFP_KERNEL); ... nla = nla_reserve(skb, NLA_UNSPEC, sizeof(struct net_dm_alert_msg)); ... msg = nla_data(nla); memset(msg, 0, al); Because al includes sizeof(struct nlattr) (the 4-byte attribute header), genlmsg_new() allocates al bytes of tailroom starting at nla. However, msg points to nla_data(nla), which is located sizeof(struct nlattr) bytes past nla. Calling memset(msg, 0, al) therefore writes al bytes starting from msg, exceeding the allocated buffer by sizeof(struct nlattr) (4 bytes) and corrupting skb_shared_info. Fix this by letting al represent only the payload length, allocating the skb with genlmsg_new(nla_total_size(al), GFP_KERNEL), and zeroing al bytes from msg.

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References

Frequently Asked Questions

What is CVE-2026-98419? +
In the Linux kernel, the following vulnerability has been resolved: drop_monitor: fix out-of-bounds write in reset_per_cpu_data() In reset_per_cpu_data(), al is computed as: al = sizeof(struct net_dm_alert_msg); al += dm_hit_limit * sizeof(struct net_dm_drop_point); al += sizeof(struct nlattr); skb = genlmsg_new(al, GFP_KERNEL); ... nla = nla_reserve(skb, NLA_UNSPEC, sizeof(struct net_dm_alert_msg)); ... msg = nla_data(nla); memset(msg, 0, al); Because al includes sizeof(struct nlattr) (the 4-byte attribute header), genlmsg_new() allocates al bytes of tailroom starting at nla. However, msg points to nla_data(nla), which is located sizeof(struct nlattr) bytes past nla. Calling memset(msg, 0, al) therefore writes al bytes starting from msg, exceeding the allocated buffer by sizeof(struct nlattr) (4 bytes) and corrupting skb_shared_info. Fix this by letting al represent only the payload length, allocating the skb with genlmsg_new(nla_total_size(al), GFP_KERNEL), and zeroing al bytes from msg.
How do I check if I'm vulnerable to CVE-2026-98419? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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