CVE-2026-5559

MEDIUMNVD 6.36.3
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

Score 6.3 from GitHub Security Advisory (severity: LOW) published 2026-04-05. NVD baseline CVSS 6.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 3 sources updated this weekElevated
6.3EG
EchelonGraph verdictPlan mitigationRemediate within your standard update timelines (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 6.3Exploit: No code on recordExposed services: Not assessed

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

A vulnerability has been found in AntaresMugisho PyBlade 0.1.8-alpha/0.1.9-alpha. The affected element is the function _is_safe_ast of the file sandbox.py of the component AST Validation. Such manipulation leads to improper neutralization of special elements used in a template engine. The attack may be performed from remote. The exploit has been disclosed to the public and may be used. The project was informed of the problem early through an issue report but has not responded yet.

CVSS v3
6.3
EG Score
6.3MEDIUMmedium confidence
EG Risk
44
EG Risk 44/100

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 (value × EchelonGraph’s weight)
Severity63% × 45%
The EG Score, 6.3 of 10.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: No fix is confirmed yet. Restrict network exposure of the affected system within your standard update timelines, and watch for a fix.
EPSS PROB
0.4%
EPSS %ILE
34th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system within your standard update timelines, and watch for a fix.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

April 5, 2026

Last Modified

July 24, 2026

Advisory Details (3)

Auto-updated Jul 25, 2026
No fix on record yet.
Web page

SSTI/RCE via Bypassed AST Validation in sandbox.py (v0.1.8-alpha through v0.2.0-alpha) · Issue #1 · AntaresMugisho/PyBlade · GitHub

https://github.com/AntaresMugisho/PyBlade/issues/1#issue-4086730906
Web page

SSTI/RCE via Bypassed AST Validation in sandbox.py (v0.1.8-alpha through v0.2.0-alpha) · Issue #1 · AntaresMugisho/PyBlade · GitHub

https://github.com/AntaresMugisho/PyBlade/issues/1
Web page

GitHub - AntaresMugisho/PyBlade: PyBlade is a lightweight template engine for Python, initially designed for Django. Inspired by Laravel's Blade and Livewire, it simplifies dynamic template creation with developer-friendly @-based directives and component support, all while prioritizing security. · GitHub

https://github.com/AntaresMugisho/PyBlade/

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
pippyblade—ghsa

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

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
pyblade0.1.8, 0.1.9
  • 0.1.8-alpha through 0.2.0-alpha: no fix on record
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 30× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 97 of 199 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 3 repeat rows among the latest 100 are merged into the row they repeat. The 102 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  2. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  3. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  4. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  5. 2026-10-12 15:55 UTCEG score recompute
  6. 2026-10-11 19:38 UTCEG score recompute
  7. 2026-10-11 16:54 UTCEG score recompute
  8. 2026-10-11 14:17 UTCEG score recompute
  9. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  10. 2026-10-11 00:22 UTCOSV refresh
  11. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  12. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  13. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  14. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  15. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  16. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  17. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  18. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  19. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  20. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  21. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  22. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  23. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  24. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  25. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.3% · 24th percentile
Show 72 more
  1. 2026-09-21 12:19 UTCOSV refresh
  2. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  3. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  4. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  5. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  6. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  7. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  8. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  9. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  10. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  11. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  12. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  13. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  14. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  15. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  16. 2026-09-02 10:04 UTCOSV refresh
  17. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  18. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  19. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  20. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  21. 2026-08-28 21:42 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  22. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  23. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  24. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  25. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  26. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  27. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  28. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  29. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  30. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  31. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  32. 2026-08-16 08:29 UTCEG score recompute
  33. 2026-08-16 08:29 UTCGHSA enrichmentGHSA-23jg-5f8m-gw8c · GitHub severity LOW · GitHub CVSS 6.3
  34. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  35. 2026-08-14 05:37 UTCEG score recompute
  36. 2026-08-14 05:37 UTCGHSA enrichmentGHSA-23jg-5f8m-gw8c · GitHub severity LOW · GitHub CVSS 6.3
  37. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  38. 2026-08-12 19:53 UTCEG score recompute
  39. 2026-08-12 19:53 UTCGHSA enrichmentGHSA-23jg-5f8m-gw8c · GitHub severity LOW · GitHub CVSS 6.3
  40. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  41. 2026-08-11 08:15 UTCEG score recompute
  42. 2026-08-11 08:15 UTCGHSA enrichmentGHSA-23jg-5f8m-gw8c · GitHub severity LOW · GitHub CVSS 6.3
  43. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  44. 2026-08-10 06:39 UTCEG score recompute
  45. 2026-08-10 06:39 UTCGHSA enrichmentGHSA-23jg-5f8m-gw8c · GitHub severity LOW · GitHub CVSS 6.3
  46. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  47. 2026-08-09 05:09 UTCEG score recompute
  48. 2026-08-09 05:09 UTCGHSA enrichmentGHSA-23jg-5f8m-gw8c · GitHub severity LOW · GitHub CVSS 6.3
  49. 2026-08-07 15:14 UTCEG score recompute
  50. 2026-08-07 15:14 UTCGHSA enrichmentGHSA-23jg-5f8m-gw8c · GitHub severity LOW · GitHub CVSS 6.3
  51. 2026-08-06 13:47 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  52. 2026-08-06 00:12 UTCEG score recompute
  53. 2026-08-06 00:12 UTCGHSA enrichmentGHSA-23jg-5f8m-gw8c · GitHub severity LOW · GitHub CVSS 6.3
  54. 2026-08-05 19:17 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  55. 2026-08-04 15:10 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  56. 2026-08-04 10:39 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  57. 2026-08-03 22:34 UTCEG score recompute
  58. 2026-08-03 22:34 UTCGHSA enrichmentGHSA-23jg-5f8m-gw8c · GitHub severity LOW · GitHub CVSS 6.3
  59. 2026-08-03 10:36 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  60. 2026-08-02 14:30 UTCEG score recompute
  61. 2026-08-02 14:30 UTCGHSA enrichmentGHSA-23jg-5f8m-gw8c · GitHub severity LOW · GitHub CVSS 6.3
  62. 2026-08-02 02:27 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  63. 2026-08-01 04:16 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  64. 2026-07-30 16:28 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  65. 2026-07-30 01:30 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  66. 2026-07-28 15:37 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  67. 2026-07-27 14:14 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  68. 2026-07-26 14:54 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  69. 2026-07-26 09:08 UTCEG score recompute
  70. 2026-07-26 09:08 UTCGHSA enrichmentGHSA-23jg-5f8m-gw8c · GitHub severity LOW · GitHub CVSS 6.3
  71. 2026-07-25 14:18 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  72. 2026-07-24 20:11 UTCNVD updateCVSS v4 → 2.1

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Frequently asked(5)

What is CVE-2026-5559?
CVE-2026-5559 is a medium-severity vulnerability; its CVE record was published on April 5, 2026. A vulnerability has been found in AntaresMugisho PyBlade 0.1.8-alpha/0.1.9-alpha. The affected element is the function issafe_ast of the file sandbox.py of the component AST Validation. Such manipulation leads to improper neutralization of special elements used in a template engine. The attack may…
When was the CVE record for CVE-2026-5559 published?
The CVE record for CVE-2026-5559 was published on April 5, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of July 24, 2026; the record at its source may have been updated since.
Is CVE-2026-5559 actively exploited?
CVE-2026-5559 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (34th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-5559?
CVE-2026-5559 has a CVSS v3 base score of 6.3 (NVD).
How do I remediate CVE-2026-5559?
No fix for CVE-2026-5559 is confirmed yet. Until one is published, restrict network exposure of the affected system — for example, keep it off the internet or limit it to trusted networks — and watch for a fix.

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