CVE-2026-17544

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 0.5%, top 58% 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, nvd
Trending — Patch released this weekElevated
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.8Exploit: Elevated riskExposed: 0

A fix is available — apply it.

Attacker-provided inputs to bccomp() could lead to an out-of-bounds write with stack and heap corruption in PHP versions from 8.4.* before 8.4.24 and from 8.5.* before 8.5.9.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
75(Track)
EG Risk 75/100SSVC: 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
Severity98% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
42%
KEV
Not listed

Published

July 30, 2026

Last Modified

August 5, 2026

Advisory Details (1)

Auto-updated Aug 19, 2026
Patch available. Sources: github.
github Patch Available

Out-of-bounds write in bccomp() via crafted operand and scale · Advisory · php/php-src · GitHub

https://github.com/php/php-src/security/advisories/GHSA-x692-q9x7-8c3f

Vendor Advisories for CVE-2026-17544(2)

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

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatphp8.4-0:8.4.24-1.el10_22026-08-19redhat
redhatphp-main-8.5.9-1.hum12026-07-28redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
php7.47.4.21-1+deb11u1 ... 7.4.33-1+deb11u9 (15 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
php8.28.2.10-1 ... 8.2.7-1~deb12u1 (28 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
php8.48.4.11-1 ... 8.4.23-1~deb13u1 (9 versions)8.4.24-1~deb13u1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
php8.48.4.11-1 ... 8.4.24-1~deb13u1 (11 versions)——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 57× in last 7d / 142× 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.

Showing the most recent 100 of 142 total refreshes for this CVE.

  1. 2026-08-21 05:13 UTCVendor advisory
  2. 2026-08-21 01:31 UTCEG score recompute
  3. 2026-08-21 01:31 UTCVendor advisory
  4. 2026-08-20 22:55 UTCEPSS rescore
  5. 2026-08-20 21:48 UTCVendor advisory
  6. 2026-08-20 18:06 UTCVendor advisory
  7. 2026-08-20 14:23 UTCVendor advisory
  8. 2026-08-20 10:20 UTCVendor advisory
  9. 2026-08-20 06:38 UTCVendor advisory
  10. 2026-08-20 02:55 UTCVendor advisory
  11. 2026-08-19 23:13 UTCVendor advisory
  12. 2026-08-19 19:30 UTCEG score recompute
  13. 2026-08-19 19:30 UTCVendor advisory
  14. 2026-08-19 17:03 UTCEPSS rescore
  15. 2026-08-19 13:11 UTCVendor advisory
  16. 2026-08-19 09:29 UTCVendor advisory
  17. 2026-08-19 05:44 UTCVendor advisory
  18. 2026-08-19 02:01 UTCVendor advisory
  19. 2026-08-18 22:15 UTCVendor advisory
  20. 2026-08-18 18:28 UTCEG score recompute
  21. 2026-08-18 18:28 UTCVendor advisory
  22. 2026-08-18 13:48 UTCEPSS rescore
  23. 2026-08-18 12:55 UTCVendor advisory
  24. 2026-08-18 08:43 UTCVendor advisory
  25. 2026-08-18 04:44 UTCVendor advisory
Show 75 more
  1. 2026-08-18 01:02 UTCVendor advisory
  2. 2026-08-17 20:53 UTCVendor advisory
  3. 2026-08-17 17:11 UTCEG score recompute
  4. 2026-08-17 17:11 UTCVendor advisory
  5. 2026-08-17 13:47 UTCEPSS rescore
  6. 2026-08-17 13:27 UTCVendor advisory
  7. 2026-08-17 09:44 UTCVendor advisory
  8. 2026-08-17 06:03 UTCVendor advisory
  9. 2026-08-17 02:14 UTCVendor advisory
  10. 2026-08-16 22:32 UTCVendor advisory
  11. 2026-08-16 18:50 UTCVendor advisory
  12. 2026-08-16 15:05 UTCEG score recompute
  13. 2026-08-16 15:05 UTCVendor advisory
  14. 2026-08-16 14:56 UTCEPSS rescore
  15. 2026-08-16 11:22 UTCVendor advisory
  16. 2026-08-16 07:40 UTCVendor advisory
  17. 2026-08-16 03:58 UTCEG score recompute
  18. 2026-08-16 03:58 UTCVendor advisory
  19. 2026-08-16 02:14 UTCEPSS rescore
  20. 2026-08-16 00:16 UTCVendor advisory
  21. 2026-08-15 20:34 UTCVendor advisory
  22. 2026-08-15 16:52 UTCVendor advisory
  23. 2026-08-15 13:10 UTCVendor advisory
  24. 2026-08-15 09:28 UTCVendor advisory
  25. 2026-08-15 05:46 UTCVendor advisory
  26. 2026-08-15 02:03 UTCEG score recompute
  27. 2026-08-15 02:03 UTCVendor advisory
  28. 2026-08-15 01:30 UTCEPSS rescore
  29. 2026-08-14 22:21 UTCVendor advisory
  30. 2026-08-14 18:39 UTCVendor advisory
  31. 2026-08-14 14:56 UTCVendor advisory
  32. 2026-08-14 11:14 UTCVendor advisory
  33. 2026-08-14 07:32 UTCVendor advisory
  34. 2026-08-14 03:50 UTCVendor advisory
  35. 2026-08-14 00:08 UTCEG score recompute
  36. 2026-08-14 00:08 UTCVendor advisory
  37. 2026-08-13 22:00 UTCEPSS rescore
  38. 2026-08-13 20:25 UTCVendor advisory
  39. 2026-08-13 16:42 UTCVendor advisory
  40. 2026-08-13 13:00 UTCVendor advisory
  41. 2026-08-13 09:17 UTCVendor advisory
  42. 2026-08-13 05:35 UTCVendor advisory
  43. 2026-08-13 01:53 UTCVendor advisory
  44. 2026-08-12 22:11 UTCVendor advisory
  45. 2026-08-12 18:29 UTCVendor advisory
  46. 2026-08-12 14:47 UTCEG score recompute
  47. 2026-08-12 14:47 UTCVendor advisory
  48. 2026-08-12 13:50 UTCEPSS rescore
  49. 2026-08-12 11:05 UTCVendor advisory
  50. 2026-08-12 07:22 UTCVendor advisory
  51. 2026-08-12 03:38 UTCVendor advisory
  52. 2026-08-11 23:56 UTCVendor advisory
  53. 2026-08-11 20:14 UTCVendor advisory
  54. 2026-08-11 16:32 UTCEG score recompute
  55. 2026-08-11 16:32 UTCVendor advisory
  56. 2026-08-11 13:42 UTCEPSS rescore
  57. 2026-08-11 12:49 UTCVendor advisory
  58. 2026-08-11 09:07 UTCVendor advisory
  59. 2026-08-11 05:25 UTCVendor advisory
  60. 2026-08-11 01:44 UTCEG score recompute
  61. 2026-08-11 01:44 UTCVendor advisory
  62. 2026-08-11 00:00 UTCEPSS rescore
  63. 2026-08-10 22:01 UTCVendor advisory
  64. 2026-08-10 18:19 UTCVendor advisory
  65. 2026-08-10 14:37 UTCVendor advisory
  66. 2026-08-10 10:55 UTCVendor advisory
  67. 2026-08-10 07:12 UTCVendor advisory
  68. 2026-08-10 03:30 UTCVendor advisory
  69. 2026-08-09 23:48 UTCVendor advisory
  70. 2026-08-09 20:06 UTCVendor advisory
  71. 2026-08-09 16:24 UTCEG score recompute
  72. 2026-08-09 16:24 UTCVendor advisory
  73. 2026-08-09 13:46 UTCEPSS rescore
  74. 2026-08-09 12:42 UTCVendor advisory
  75. 2026-08-09 09:00 UTCVendor advisory

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCBoreas37/CVE-2026-17544-PoC
    First seen Aug 12, 2026

    CVE-2026-17544 — PHP bcmath bccomp() OOB write (stack smashing). Verified: crash on 8.4.23/8.5.8, fixed in 8.4.24. GHSA-x692-q9x7-8c3f

    Open source ↗

Frequently asked(5)

What is CVE-2026-17544?
CVE-2026-17544 is a critical vulnerability published on July 30, 2026. Attacker-provided inputs to bccomp() could lead to an out-of-bounds write with stack and heap corruption in PHP versions from 8.4. before 8.4.24 and from 8.5. before 8.5.9.
When was CVE-2026-17544 disclosed?
CVE-2026-17544 was first published in the National Vulnerability Database on July 30, 2026, with the most recent update on August 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-17544 actively exploited?
CVE-2026-17544 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 57.8% of all scored CVEs.
What is the CVSS score of CVE-2026-17544?
CVE-2026-17544 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-17544?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-17544, 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-2026-17544

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