CVE-2026-59729

MEDIUMPre-NVD 5.15.1—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 75% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
5.1EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.1Exploit: Elevated riskExposed: 0

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

Astro is a web framework for content-driven websites. Versions prior to 7.0.6 are vulnerable to XSS through unescaped spread attribute names in renderHTMLElement. The fix for CVE-2026-54298 (GHSA-jrpj-wcv7-9fh9) added an INVALID_ATTR_NAME_CHAR guard to addAttribute() so that spread-prop attribute names containing "' >/= or whitespace are dropped. A second attribute-rendering path, renderHTMLElement() in packages/astro/src/runtime/server/render/dom.ts, has its own inline attribute loop that does not go through addAttribute() and was not updated. It interpolates the attribute name unescaped and only escapes the value, so untrusted prop keys spread onto a native-HTMLElement-subclass component can still break out of the attribute context. This issue has been fixed in version 7.0.6.

CVSS v3
5.1
EG Score
5.1(medium)
EG Risk
39(Track)
EG Risk 39/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity51% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
25%
KEV
Not listed

Published

July 20, 2026

Last Modified

July 28, 2026

Advisory Details (4)

Auto-updated Jul 27, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_pr, github_commit, github_release.
github_release Patch Available

[email protected]

Patch available: withastro/astro [email protected]

https://github.com/withastro/astro/releases/tag/[email protected]
github_commit Patch Available

commit 5240e26c9dd9 (withastro/astro)

Patch available: withastro/astro [email protected] (contains commit 5240e26c9dd9)

https://github.com/withastro/astro/commit/5240e26c9dd91f9bc7140dcfacdb48d5a132830d
github_pr Patch Available

Validate attribute names on custom HTML elements during SSR

Patch available: withastro/astro [email protected] (PR #17251 merged 2026-07-02)

https://github.com/withastro/astro/pull/17251
github Patch Available🟡 PoC Available

XSS via unescaped spread attribute names in custom element rendering · Advisory · withastro/astro · GitHub

https://github.com/withastro/astro/security/advisories/GHSA-f48w-9m4c-m7f5

Vendor Advisories for CVE-2026-59729(1)

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

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
astro—7.0.6—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 46× 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. 2026-09-11 14:53 UTCEPSS rescore
  2. 2026-09-11 09:17 UTCEG score recompute
  3. 2026-09-10 09:35 UTCEPSS rescore
  4. 2026-09-09 11:45 UTCEG score recompute
  5. 2026-09-08 22:01 UTCEPSS rescore
  6. 2026-09-07 22:47 UTCEG score recompute
  7. 2026-09-07 16:01 UTCEPSS rescore
  8. 2026-09-06 13:47 UTCEPSS rescore
  9. 2026-09-06 11:36 UTCEG score recompute
  10. 2026-09-05 09:19 UTCEG score recompute
  11. 2026-09-04 05:07 UTCEPSS rescore
  12. 2026-09-02 14:12 UTCEPSS rescore
  13. 2026-09-02 01:02 UTCEG score recompute
  14. 2026-09-01 13:54 UTCEPSS rescore
  15. 2026-09-01 04:40 UTCEPSS rescore
  16. 2026-08-31 04:43 UTCEG score recompute
  17. 2026-08-30 19:17 UTCEPSS rescore
  18. 2026-08-30 02:28 UTCEG score recompute
  19. 2026-08-30 01:22 UTCEPSS rescore
  20. 2026-08-28 21:42 UTCEPSS rescore
  21. 2026-08-27 15:12 UTCEG score recompute
  22. 2026-08-27 14:25 UTCEPSS rescore
  23. 2026-08-26 14:46 UTCEPSS rescore
  24. 2026-08-26 12:43 UTCEG score recompute
  25. 2026-08-25 13:49 UTCEPSS rescore
Show 52 more
  1. 2026-08-25 10:04 UTCEG score recompute
  2. 2026-08-23 05:33 UTCEG score recompute
  3. 2026-08-23 00:19 UTCEPSS rescore
  4. 2026-08-22 03:17 UTCEG score recompute
  5. 2026-08-21 23:49 UTCEPSS rescore
  6. 2026-08-21 01:01 UTCEG score recompute
  7. 2026-08-20 22:55 UTCEPSS rescore
  8. 2026-08-19 22:46 UTCEG score recompute
  9. 2026-08-19 17:04 UTCEPSS rescore
  10. 2026-08-18 19:35 UTCEG score recompute
  11. 2026-08-18 13:48 UTCEPSS rescore
  12. 2026-08-17 13:47 UTCEPSS rescore
  13. 2026-08-17 11:46 UTCEG score recompute
  14. 2026-08-16 14:56 UTCEPSS rescore
  15. 2026-08-16 09:31 UTCEG score recompute
  16. 2026-08-16 02:14 UTCEPSS rescore
  17. 2026-08-15 07:16 UTCEG score recompute
  18. 2026-08-15 01:30 UTCEPSS rescore
  19. 2026-08-14 03:56 UTCEG score recompute
  20. 2026-08-13 22:00 UTCEPSS rescore
  21. 2026-08-13 01:41 UTCEG score recompute
  22. 2026-08-12 13:51 UTCEPSS rescore
  23. 2026-08-11 23:26 UTCEG score recompute
  24. 2026-08-11 00:00 UTCEPSS rescore
  25. 2026-08-09 18:55 UTCEG score recompute
  26. 2026-08-09 13:46 UTCEPSS rescore
  27. 2026-08-08 16:40 UTCEG score recompute
  28. 2026-08-08 16:37 UTCEPSS rescore
  29. 2026-08-07 14:24 UTCEG score recompute
  30. 2026-08-06 13:47 UTCEPSS rescore
  31. 2026-08-06 12:09 UTCEG score recompute
  32. 2026-08-05 19:17 UTCEPSS rescore
  33. 2026-08-05 09:53 UTCEG score recompute
  34. 2026-08-04 15:10 UTCEPSS rescore
  35. 2026-08-04 10:39 UTCEPSS rescore
  36. 2026-08-03 04:09 UTCEG score recompute
  37. 2026-08-02 02:27 UTCEPSS rescore
  38. 2026-08-02 01:52 UTCEG score recompute
  39. 2026-08-01 04:16 UTCEPSS rescore
  40. 2026-07-30 21:21 UTCEG score recompute
  41. 2026-07-30 16:28 UTCEPSS rescore
  42. 2026-07-30 01:30 UTCEPSS rescore
  43. 2026-07-30 01:30 UTCEPSS rescore
  44. 2026-07-28 15:46 UTCEG score recompute
  45. 2026-07-28 15:37 UTCEPSS rescore
  46. 2026-07-28 14:42 UTCEG score recompute
  47. 2026-07-27 20:22 UTCEG score recompute
  48. 2026-07-27 19:56 UTCEG score recompute▲ 5.10
  49. 2026-07-27 19:54 UTCMITRE cvelistV5CVSS v3 → 5.1 · CVSS v4 → 5.1
  50. 2026-07-26 10:45 UTCEG score recompute
  51. 2026-07-23 03:21 UTCEG score recompute
  52. 2026-07-20 23:33 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-59729?
CVE-2026-59729 is a medium vulnerability published on July 20, 2026. Astro is a web framework for content-driven websites. Versions prior to 7.0.6 are vulnerable to XSS through unescaped spread attribute names in renderHTMLElement. The fix for CVE-2026-54298 (GHSA-jrpj-wcv7-9fh9) added an INVALIDATTRNAME_CHAR guard to addAttribute() so that spread-prop attribute…
When was CVE-2026-59729 disclosed?
CVE-2026-59729 was first published in the National Vulnerability Database on July 20, 2026, with the most recent update on July 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-59729 actively exploited?
CVE-2026-59729 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 74.9% of all scored CVEs.
What is the CVSS score of CVE-2026-59729?
CVE-2026-59729 has a CVSS v3 base score of 5.1 (NVD).
How do I remediate CVE-2026-59729?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-59729, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-59729

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