Answer in brief
CVE-2025-39797 records a High severity (CVSS 7.8) vulnerability in xfrm: Duplicate SPI Handling. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fb58962aa3b9359988c7b5b15a971fd9ad5b0ecd || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3d8090bb53424432fa788fe9a49e8ceca74f0544 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2fc5b54368a1bf1d2d74b4d3b8eea5309a653e38 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c67d4e7a8f90fb6361ca89d4d5c9a28f4e935e47 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <29e9158f91f99057dbd35db5e8674d93b38549fe || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <94f39804d891cffe4ce17737d295f3b195bc7299 | fb58962aa3b9359988c7b5b15a971fd9ad5b0ecd, 3d8090bb53424432fa788fe9a49e8ceca74f0544, 2fc5b54368a1bf1d2d74b4d3b8eea5309a653e38, c67d4e7a8f90fb6361ca89d4d5c9a28f4e935e47, 29e9158f91f99057dbd35db5e8674d93b38549fe, 94f39804d891cffe4ce17737d295f3b195bc7299 |
| Linux/Linuxgeneric | 2.6.12 | Not reported |
Published upstream
Sep 12, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 30, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 28, 2026
In 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.
Quoted source text, attributed separately from HOL analysis.