CVE-2026-53263

MEDIUMNVD 5.55.5—
EchelonGraph scoreHIGH confidence

Score 5.5 from GitHub Security Advisory published 2026-06-25. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
5.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.5Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

In the Linux kernel, the following vulnerability has been resolved:

6lowpan: fix off-by-one in multicast context address compression

The second memcpy in lowpan_iphc_mcast_ctx_addr_compress() uses &data[1] as destination and &ipaddr->s6_addr[11] as source, but both should be offset by one: &data[2] and &ipaddr->s6_addr[12] respectively.

This off-by-one has two consequences:

  • data[1] is overwritten with s6_addr[11], corrupting the RIID
field in the compressed multicast address
  • data[5] is never written, so uninitialized kernel stack memory
is transmitted over the network via lowpan_push_hc_data(), leaking kernel stack contents

The correct inline data layout must match what the decompression function lowpan_uncompress_multicast_ctx_daddr() expects: data[0..1] = s6_addr[1..2] (flags/scope + RIID) data[2..5] = s6_addr[12..15] (group ID)

Also zero-initialize the data array as a defensive measure against similar bugs in the future.

CVSS v3
5.5
EG Score
5.5(high)
EG Risk
—
EPSS
2.1%
KEV
Not listed

Published

June 25, 2026

Last Modified

July 8, 2026

Advisory Details (8)

Auto-updated Jul 8, 2026
No patch confirmed yet.
generic

6lowpan: fix off-by-one in multicast context address compression - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/f24a58c72a45f4c109f3557a760cc4b60b7a6037
generic

6lowpan: fix off-by-one in multicast context address compression - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/dcb1bec1c32ee5c3878354e087cf5dbee2b7c7af
generic

6lowpan: fix off-by-one in multicast context address compression - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/da8cbb64b47e9066b40af0de170901caf17b768c
generic

6lowpan: fix off-by-one in multicast context address compression - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/da8808463882c3f3c357b072e25053c2121f1419
generic

6lowpan: fix off-by-one in multicast context address compression - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c32f30ef5e66adbfa102348e2e8a23776eb007cb
generic

6lowpan: fix off-by-one in multicast context address compression - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/4485d79617520d84ba5a14515e2b5136007d6deb
generic

6lowpan: fix off-by-one in multicast context address compression - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/2a58899d11009bffc7b4b32a571858f381121837
generic

6lowpan: fix off-by-one in multicast context address compression - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/06ce6fc106b16dec9b535950db626261be865e5b

Vendor Advisories for CVE-2026-53263(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 10× in last 7d / 67× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-22 14:08 UTCEPSS rescore
  2. 2026-07-21 15:25 UTCEPSS rescore
  3. 2026-07-20 17:08 UTCEPSS rescore
  4. 2026-07-19 14:31 UTCEPSS rescore
  5. 2026-07-19 14:31 UTCEPSS rescore
  6. 2026-07-19 02:29 UTCEPSS rescore
  7. 2026-07-18 10:04 UTCEPSS rescore
  8. 2026-07-16 20:50 UTCVendor advisory
  9. 2026-07-16 20:50 UTCGHSA enrichment
  10. 2026-07-16 17:03 UTCEPSS rescore
  11. 2026-07-15 22:15 UTCVendor advisory
  12. 2026-07-15 22:15 UTCGHSA enrichment
  13. 2026-07-15 16:57 UTCEPSS rescore
  14. 2026-07-15 16:57 UTCEPSS rescore
  15. 2026-07-14 23:39 UTCVendor advisory
  16. 2026-07-14 23:39 UTCGHSA enrichment
  17. 2026-07-14 00:48 UTCGHSA enrichment
  18. 2026-07-13 22:31 UTCEPSS rescore
  19. 2026-07-13 06:13 UTCEPSS rescore
  20. 2026-07-13 06:13 UTCEPSS rescore
  21. 2026-07-13 02:12 UTCVendor advisory
  22. 2026-07-13 02:12 UTCGHSA enrichment
  23. 2026-07-12 03:36 UTCVendor advisory
  24. 2026-07-12 03:36 UTCGHSA enrichment
  25. 2026-07-11 08:27 UTCEPSS rescore
Show 42 more
  1. 2026-07-11 08:27 UTCEPSS rescore
  2. 2026-07-11 04:59 UTCVendor advisory
  3. 2026-07-11 04:59 UTCGHSA enrichment
  4. 2026-07-10 06:23 UTCVendor advisory
  5. 2026-07-10 06:23 UTCGHSA enrichment
  6. 2026-07-09 19:10 UTCEPSS rescore
  7. 2026-07-09 19:10 UTCEPSS rescore
  8. 2026-07-09 07:47 UTCVendor advisory
  9. 2026-07-09 07:47 UTCGHSA enrichment
  10. 2026-07-08 15:16 UTCEPSS rescore
  11. 2026-07-08 15:16 UTCEPSS rescore
  12. 2026-07-08 09:11 UTCEG score recompute▲ 5.50
  13. 2026-07-08 09:11 UTCVendor advisory
  14. 2026-07-08 09:10 UTCGHSA enrichment
  15. 2026-07-08 04:32 UTCNVD updateCVSS v3 → 5.5 · severity → MEDIUM
  16. 2026-07-07 13:46 UTCEPSS rescore
  17. 2026-07-07 13:46 UTCEPSS rescore
  18. 2026-07-06 16:27 UTCEPSS rescore
  19. 2026-07-06 16:27 UTCEPSS rescore
  20. 2026-07-06 02:23 UTCEPSS rescore
  21. 2026-07-06 02:23 UTCEPSS rescore
  22. 2026-07-05 03:24 UTCVendor advisory
  23. 2026-07-05 03:24 UTCGHSA enrichment
  24. 2026-07-05 02:31 UTCEPSS rescore
  25. 2026-07-05 02:30 UTCEPSS rescore
  26. 2026-07-04 06:31 UTCEPSS rescore
  27. 2026-07-04 06:31 UTCEPSS rescore
  28. 2026-07-01 21:36 UTCVendor advisory
  29. 2026-07-01 21:36 UTCGHSA enrichment
  30. 2026-07-01 15:07 UTCEPSS rescore
  31. 2026-06-30 23:22 UTCEPSS rescore
  32. 2026-06-29 14:06 UTCEPSS rescore
  33. 2026-06-29 14:06 UTCEPSS rescore
  34. 2026-06-28 15:50 UTCVendor advisory
  35. 2026-06-28 15:50 UTCGHSA enrichment
  36. 2026-06-28 14:07 UTCEPSS rescore
  37. 2026-06-28 04:56 UTCEPSS rescore
  38. 2026-06-28 04:56 UTCEPSS rescore
  39. 2026-06-27 03:08 UTCEPSS rescore
  40. 2026-06-25 13:49 UTCEPSS rescore
  41. 2026-06-25 10:03 UTCEG score recompute
  42. 2026-06-25 10:03 UTCGHSA enrichment

Frequently asked(5)

What is CVE-2026-53263?
CVE-2026-53263 is a medium vulnerability published on June 25, 2026. In the Linux kernel, the following vulnerability has been resolved: 6lowpan: fix off-by-one in multicast context address compression The second memcpy in lowpaniphcmcastctxaddr_compress() uses &data[1] as destination and &ipaddr->s6_addr[11] as source, but both should be offset by one: &data[2] and…
When was CVE-2026-53263 disclosed?
CVE-2026-53263 was first published in the National Vulnerability Database on June 25, 2026, with the most recent update on July 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-53263 actively exploited?
CVE-2026-53263 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-53263?
CVE-2026-53263 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-53263?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53263, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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