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NVD / CVE Program· CNA Linux

CVE-2022-49340: ip_gre: test csum_start instead of transport header

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.28% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 0c92d813c7c9ca2212ecd879232e7d87362fce98, 0ffa268724656633af5f37a38c212326d98ebe8c, 3d08bc3a5d9b2106f5c8bcf1adb73147824aa006.

Low priority for now. Upgrade to Linux Linux 0c92d813c7c9ca2212ecd879232e7d87362fce98, 0ffa268724656633af5f37a38c212326d98ebe8c, 3d08bc3a5d9b2106f5c8bcf1adb73147824aa006 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: ip_gre: test csum_start instead of transport header GRE with TUNNEL_CSUM will apply local checksum offload on CHECKSUM_PARTIAL packets. ipgre_xmit must validate csum_start after an optional skb_pull, else lco_csum may trigger an overflow. The original check was if (csum && skb_checksum_start(skb) < skb->data) return -EINVAL; This had false positives when skb_checksum_start is undefined: when ip_summed is not CHECKSUM_PARTIAL. A discussed refinement was straightforward if (csum && skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_start(skb) < skb->data) return -EINVAL; But was eventually revised more thoroughly: - restrict the check to the only branch where needed, in an uncommon GRE path that uses header_ops and calls skb_pull. - test skb_transport_header, which is set along with csum_start in skb_partial_csum_set in the normal header_ops datapath. Turns out skbs can arrive in this branch without the transport header set, e.g., through BPF redirection. Revise the check back to check csum_start directly, and only if CHECKSUM_PARTIAL. Do leave the check in the updated location. Check field regardless of whether TUNNEL_CSUM is configured.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Feb 26, 2025
Updated
Aug 5, 2026
EPSS
0.2% · 20th percentile
CWE
—

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CNA vs NVD score

NVD
5.5
CNA · Linux
7.1
1.6 point gap

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

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  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel4.19.207 and later · before 4.19.247
  • linux linux kernel5.4.148 and later · before 5.4.198
  • linux linux kernel5.10.68 and later · before 5.10.122
  • linux linux kernel5.14.7 and later · before 5.15.47
  • linux linux kernel5.16 and later · before 5.17.15
  • linux linux kernel5.18 and later · before 5.18.4
  • linux linux kernel5.19

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 4bf5d5224ffca069df4501ba5fcc6ded9c002ead, 5.15affected
    • 774430026bd9a472d08c5d3c33351a782315771a and later · before 7596bd7920985f7fc8579a92e48bc53ce4475b21affected · git
    • 3d32ce5472bb2ca720bef84089b85f76a705fd1a and later · before 3d08bc3a5d9b2106f5c8bcf1adb73147824aa006affected · git
    • 87b34cd6485192777f632f92d592f2a71d8801a6 and later · before fbeb8dfa8b87ef259eef0c89e39b53962a3cf604affected · git
    • 8a0ed250f911da31a2aef52101bc707846a800ff and later · before e6b6f98fc7605c06c0a3baa70f62c534d7b4ce58affected · git
    • 8a0ed250f911da31a2aef52101bc707846a800ff and later · before 0c92d813c7c9ca2212ecd879232e7d87362fce98affected · git
    • 8a0ed250f911da31a2aef52101bc707846a800ff and later · before 0ffa268724656633af5f37a38c212326d98ebe8caffected · git
    • 8a0ed250f911da31a2aef52101bc707846a800ff and later · before 8d21e9963bec1aad2280cdd034c8993033ef2948affected · git
    • 4.19.207 and later · before 4.19.247affected · semver
    • 5.4.148 and later · before 5.4.198affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.18.5-15.18.5-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2022-49337Feb 26, 2025 · ocfs2: dlmfs: fix error handling of user_dlm_destroy_lock
    22Monitor
  • ← EarlierCVE-2022-49338Feb 26, 2025 · net/mlx5e: CT: Fix cleanup of CT before cleanup of TC ct rules
    22Monitor
  • Later →CVE-2022-49342Feb 26, 2025 · net: ethernet: bgmac: Fix refcount leak in bcma_mdio_mii_register
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux0c92d813c7c9ca2212ecd879232e7d87362fce98Vendor (CNA)
Linux Linux0ffa268724656633af5f37a38c212326d98ebe8cVendor (CNA)
Linux Linux3d08bc3a5d9b2106f5c8bcf1adb73147824aa006Vendor (CNA)
Linux Linux4.19.247Vendor (CNA)
Linux Linux5.10.122Vendor (CNA)
Linux Linux5.15Vendor (CNA)
Linux Linux5.4.198Vendor (CNA)
Linux Linux7596bd7920985f7fc8579a92e48bc53ce4475b21Vendor (CNA)
Linux Linux8d21e9963bec1aad2280cdd034c8993033ef2948Vendor (CNA)
Linux Linuxe6b6f98fc7605c06c0a3baa70f62c534d7b4ce58Vendor (CNA)
Linux Linuxfbeb8dfa8b87ef259eef0c89e39b53962a3cf604Vendor (CNA)
debian:linux5.18.5-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records