ip_gre: test csum_start instead of transport header
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.
- Published
- Feb 26, 2025
- Updated
- Aug 5, 2026
- EPSS
- 0.3% · 19th percentile
- CWE
- —
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Report tools
Action score
22
Monitor
Low priority for now.
- CVSS
- 22 / 40 · 5.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
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.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| linux | linux kernel | cpe:2.3:o:linux:linux_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.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | linux | before 5.18.5-1 | 5.18.5-1 |
Same product
linux: all recordsOther highest-scoring records for the same primary product.
- 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 KEV89Now
- CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV85Now
- CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV83Now
- CVE-2019-13272In the Linux kernel before 5.1.17, ptrace_link in kernel/ptrace.c mishandles the recording of the credentials of a process that wants to creKEV77This week
- CVE-2013-6282The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the v6k and v7 ARM platforms do not validate certain addKEV77This week
- CVE-2013-2094The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9 uses an incorrect integer data type, which allows loKEV77This week
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Linux Linux | 0c92d813c7c9ca2212ecd879232e7d87362fce98 | Vendor (CNA) |
| Linux Linux | 0ffa268724656633af5f37a38c212326d98ebe8c | Vendor (CNA) |
| Linux Linux | 3d08bc3a5d9b2106f5c8bcf1adb73147824aa006 | Vendor (CNA) |
| Linux Linux | 4.19.247 | Vendor (CNA) |
| Linux Linux | 5.10.122 | Vendor (CNA) |
| Linux Linux | 5.15 | Vendor (CNA) |
| Linux Linux | 5.4.198 | Vendor (CNA) |
| Linux Linux | 7596bd7920985f7fc8579a92e48bc53ce4475b21 | Vendor (CNA) |
| Linux Linux | 8d21e9963bec1aad2280cdd034c8993033ef2948 | Vendor (CNA) |
| Linux Linux | e6b6f98fc7605c06c0a3baa70f62c534d7b4ce58 | Vendor (CNA) |
| Linux Linux | fbeb8dfa8b87ef259eef0c89e39b53962a3cf604 | Vendor (CNA) |
| debian:linux | 5.18.5-1 · Debian:12 | Package 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.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
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 researchersFinders, 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.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
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References
- git.kernel.org/stable/c/0c92d813c7c9ca2212ecd879232e7d87362fce98
- git.kernel.org/stable/c/0ffa268724656633af5f37a38c212326d98ebe8c
- git.kernel.org/stable/c/3d08bc3a5d9b2106f5c8bcf1adb73147824aa006
- git.kernel.org/stable/c/7596bd7920985f7fc8579a92e48bc53ce4475b21
- git.kernel.org/stable/c/8d21e9963bec1aad2280cdd034c8993033ef2948
- git.kernel.org/stable/c/e6b6f98fc7605c06c0a3baa70f62c534d7b4ce58
- git.kernel.org/stable/c/fbeb8dfa8b87ef259eef0c89e39b53962a3cf604
Vendor advisories and official records. Exploit/PoC links are deliberately left out.