Kernel RCE risk; affects broad Linux deployments; foundational impact.
CVE-2026-43139
Linux kernel xfrm6: uninitialized saddr may cause RCE.
Is CVE-2026-43139 being exploited?
Not confirmed. CVE-2026-43139 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.38% probability of exploitation in the next 30 days.
How severe is CVE-2026-43139?
CVE-2026-43139 is rated High with a CVSS score of 8.6. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-43139?
Yes. A fix has been recorded for CVE-2026-43139. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-43139 affect?
CVE-2026-43139 affects Linux kernel (xfrm6 related). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-43139?
Update kernel to patched release and reboot
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution via IPsec/xfrm path due to uninitialized saddr in xfrm6_get_saddr().
Patch when possible
- affected>= a1e59abf824969554b90facd44a4ab16e265afa4 and < 4f28141786e1fe884ce42a5197ba9beed540f0ea
- affected>= a1e59abf824969554b90facd44a4ab16e265afa4 and < 6535867673bf301d52aa00593a4d1d18cc3922fa
- affected>= a1e59abf824969554b90facd44a4ab16e265afa4 and < eb2ee15290af14c60b45cf2b73f5687d1d077d9b
- affected>= a1e59abf824969554b90facd44a4ab16e265afa4 and < 719918fc88df6da023dfff370cd965151a5afd7f
- affected>= a1e59abf824969554b90facd44a4ab16e265afa4 and < dc0abce055134cb83b0d981d31ceb20dda419787
- affected>= a1e59abf824969554b90facd44a4ab16e265afa4 and < c7221e7bd8fc2ef38a0b27be580d9d202281306b
- affected>= a1e59abf824969554b90facd44a4ab16e265afa4 and < 3dcd1664ac15eee6a690daec7c4ffc59190406f7
- affected>= a1e59abf824969554b90facd44a4ab16e265afa4 and < 1799d8abeabc68ec05679292aaf6cba93b343c05
- affected2.6.19
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.