CVE-2026-90078

UNRATEDCVSS · not yet scoredTrending — 4 sources updated this week
—
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • No CVSS published and no exploitation signals yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS v2: —Exploit: None knownExposed services: Not assessed

No fix is confirmed yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for the fix.

In the Linux kernel, the following vulnerability has been resolved:

net/sched: act_skbmod: fix length calculations and avoid invalid header warnings

syzbot reported a warning in skb_network_header_len() triggered by tcf_skbmod_act():

!skb_transport_header_was_set(skb) WARNING: CPU: 0 PID: 14949 at include/linux/skbuff.h:3243 skb_network_header_len include/linux/skbuff.h:3243 [inline] WARNING: CPU: 0 PID: 14949 at net/sched/act_skbmod.c:55 tcf_skbmod_act+0xfe8/0x1810 net/sched/act_skbmod.c:55

There are a few issues in tcf_skbmod_act():

  • Calling skb_network_header_len() assumes skb->transport_header is set,
which is not guaranteed when tcf_skbmod_act() runs at TC ingress.
  • Unconditionally calling skb_mac_header_len() at the beginning of
tcf_skbmod_act() triggers a warning on L3 devices (e.g. TUN) where the MAC header is unset, evaluating to an underflowed garbage length.
  • On TC ingress, skb->data points to the network header. Adding the MAC
header length to the IP header length causes skb_ensure_writable() to request more bytes than the actual IP packet length, dropping valid short packets (e.g. 28-byte UDP/IPv4 packets).

Fix these by:

  • Using skb_network_offset(skb) + sizeof(struct iphdr/ipv6hdr) for
SKBMOD_F_ECN so that the required length is correctly calculated on both ingress (offset == 0) and egress (offset == mac_len).
  • Setting max_edit_len to ETH_HLEN for Ethernet header modifications
after validating ARPHRD_ETHER.

CVSS v3
—
EchelonGraph score
Not yet assessedNo source has published severity data for this CVE yet — no CVSS score from NVD or a CNA, no GitHub advisory, and it is not in CISA KEV. This is not a rating of zero; we cannot assess it yet.
EG Score
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EG Risk
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EPSS PROB
0.2%
EPSS %ILE
9th
KEV
Not listed

Published

September 17, 2026

Last Modified

September 17, 2026

References (7)

Vendor Advisories for CVE-2026-90078(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(4 across 3 ecosystems)
Debian:12(2)
PackageVulnerable rangeFix by version rangeDependents
linux6.1.106-1 ... 7.2~rc7-1~exp1 (360 versions)
  • every version on: no fix on record
—
linux-6.126.12.100-1~deb12u1, 6.12.101-1~deb12u1, 6.12.107-1~deb12u1
  • every version up to 6.12.111-1~deb12u1: fixed in 6.12.111-1~deb12u1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 6.12.96-1 (35 versions)
  • every version up to 6.12.111-1: fixed in 6.12.111-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.2~rc7-1~exp1 (179 versions)
  • every version up to 7.2.6-1: fixed in 7.2.6-1
—

Data Freshness Timeline

(refreshed 10× in last 7d / 28× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-04 23:22 UTCEPSS rescore
  2. 2026-10-03 10:00 UTCVendor advisory
  3. 2026-10-03 10:00 UTCGHSA enrichment
  4. 2026-10-01 19:51 UTCEPSS rescore
  5. 2026-09-30 15:04 UTCEPSS rescore
  6. 2026-09-30 06:40 UTCEG score recompute
  7. 2026-09-30 06:40 UTCVendor advisory
  8. 2026-09-30 06:40 UTCGHSA enrichment
  9. 2026-09-28 13:52 UTCEPSS rescore
  10. 2026-09-28 13:52 UTCEPSS rescore
  11. 2026-09-27 13:49 UTCEPSS rescore
  12. 2026-09-27 03:30 UTCVendor advisory
  13. 2026-09-27 03:30 UTCGHSA enrichment
  14. 2026-09-26 15:59 UTCEPSS rescore
  15. 2026-09-24 14:04 UTCEPSS rescore
  16. 2026-09-24 00:16 UTCVendor advisory
  17. 2026-09-24 00:16 UTCGHSA enrichment
  18. 2026-09-23 17:54 UTCEPSS rescore
  19. 2026-09-22 16:01 UTCEPSS rescore
  20. 2026-09-21 21:09 UTCEPSS rescore
  21. 2026-09-20 21:07 UTCEG score recompute
  22. 2026-09-20 21:07 UTCVendor advisory
  23. 2026-09-20 21:06 UTCGHSA enrichment
  24. 2026-09-20 20:16 UTCEPSS rescore
  25. 2026-09-18 19:28 UTCEPSS rescore
Show 3 more
  1. 2026-09-17 17:23 UTCNVD update
  2. 2026-09-17 16:52 UTCEG score recompute
  3. 2026-09-17 16:19 UTCMITRE cvelistV5first tracked

Frequently asked(4)

What is CVE-2026-90078?
CVE-2026-90078 is a publicly disclosed vulnerability published on September 17, 2026. In the Linux kernel, the following vulnerability has been resolved: net/sched: act_skbmod: fix length calculations and avoid invalid header warnings syzbot reported a warning in skbnetworkheader_len() triggered by tcfskbmodact(): !skbtransportheaderwasset(skb) WARNING: CPU: 0 PID: 14949 at…
When was CVE-2026-90078 disclosed?
CVE-2026-90078 was first published on September 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-90078 actively exploited?
CVE-2026-90078 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (9th percentile of EPSS-scored CVEs).
How do I remediate CVE-2026-90078?
No fix for CVE-2026-90078 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-90078 are linked in the Vendor Advisories panel on this page.

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