GHSA-P94F-8HPH-RVRP
Vulnerability from github – Published: 2025-09-12 18:31 – Updated: 2026-10-30 15:32In the Linux kernel, the following vulnerability has been resolved:
xfrm: Duplicate SPI Handling
The issue originates when Strongswan initiates an XFRM_MSG_ALLOCSPI Netlink message, which triggers the kernel function xfrm_alloc_spi(). This function is expected to ensure uniqueness of the Security Parameter Index (SPI) for inbound Security Associations (SAs). However, it can return success even when the requested SPI is already in use, leading to duplicate SPIs assigned to multiple inbound SAs, differentiated only by their destination addresses.
This behavior causes inconsistencies during SPI lookups for inbound packets. Since the lookup may return an arbitrary SA among those with the same SPI, packet processing can fail, resulting in packet drops.
According to RFC 4301 section 4.4.2 , for inbound processing a unicast SA is uniquely identified by the SPI and optionally protocol.
Reproducing the Issue Reliably: To consistently reproduce the problem, restrict the available SPI range in charon.conf : spi_min = 0x10000000 spi_max = 0x10000002 This limits the system to only 2 usable SPI values. Next, create more than 2 Child SA. each using unique pair of src/dst address. As soon as the 3rd Child SA is initiated, it will be assigned a duplicate SPI, since the SPI pool is already exhausted. With a narrow SPI range, the issue is consistently reproducible. With a broader/default range, it becomes rare and unpredictable.
Current implementation: xfrm_spi_hash() lookup function computes hash using daddr, proto, and family. So if two SAs have the same SPI but different destination addresses, then they will: a. Hash into different buckets b. Be stored in different linked lists (byspi + h) c. Not be seen in the same hlist_for_each_entry_rcu() iteration. As a result, the lookup will result in NULL and kernel allows that Duplicate SPI
Proposed Change: xfrm_state_lookup_spi_proto() does a truly global search - across all states, regardless of hash bucket and matches SPI and proto.
{
"affected": [],
"aliases": [
"CVE-2025-39797"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-09-12T16:15:34Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: Duplicate SPI Handling\n\nThe issue originates when Strongswan initiates an XFRM_MSG_ALLOCSPI\nNetlink message, which triggers the kernel function xfrm_alloc_spi().\nThis function is expected to ensure uniqueness of the Security Parameter\nIndex (SPI) for inbound Security Associations (SAs). However, it can\nreturn success even when the requested SPI is already in use, leading\nto duplicate SPIs assigned to multiple inbound SAs, differentiated\nonly by their destination addresses.\n\nThis behavior causes inconsistencies during SPI lookups for inbound packets.\nSince the lookup may return an arbitrary SA among those with the same SPI,\npacket processing can fail, resulting in packet drops.\n\nAccording to RFC 4301 section 4.4.2 , for inbound processing a unicast SA\nis uniquely identified by the SPI and optionally protocol.\n\nReproducing the Issue Reliably:\nTo consistently reproduce the problem, restrict the available SPI range in\ncharon.conf : spi_min = 0x10000000 spi_max = 0x10000002\nThis limits the system to only 2 usable SPI values.\nNext, create more than 2 Child SA. each using unique pair of src/dst address.\nAs soon as the 3rd Child SA is initiated, it will be assigned a duplicate\nSPI, since the SPI pool is already exhausted.\nWith a narrow SPI range, the issue is consistently reproducible.\nWith a broader/default range, it becomes rare and unpredictable.\n\nCurrent implementation:\nxfrm_spi_hash() lookup function computes hash using daddr, proto, and family.\nSo if two SAs have the same SPI but different destination addresses, then\nthey will:\na. Hash into different buckets\nb. Be stored in different linked lists (byspi + h)\nc. Not be seen in the same hlist_for_each_entry_rcu() iteration.\nAs a result, the lookup will result in NULL and kernel allows that Duplicate SPI\n\nProposed Change:\nxfrm_state_lookup_spi_proto() does a truly global search - across all states,\nregardless of hash bucket and matches SPI and proto.",
"id": "GHSA-p94f-8hph-rvrp",
"modified": "2026-10-30T15:32:14Z",
"published": "2025-09-12T18:31:10Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-39797"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/29e9158f91f99057dbd35db5e8674d93b38549fe"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2fc5b54368a1bf1d2d74b4d3b8eea5309a653e38"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3d8090bb53424432fa788fe9a49e8ceca74f0544"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/94f39804d891cffe4ce17737d295f3b195bc7299"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c67d4e7a8f90fb6361ca89d4d5c9a28f4e935e47"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fb58962aa3b9359988c7b5b15a971fd9ad5b0ecd"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
How durations are calculated
Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.
Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.
Loading timeline…
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.