CVE-2026-63443

HIGHPre-NVD 8.38.3—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 64% 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
Trending — 3 sources updated this week
8.3EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.3Exploit: None knownExposed: 0

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

Coder allows organizations to provision remote development environments via Terraform. Prior to 2.29.19, 2.32.9, 2.33.10, and 2.34.4, agentConn.apiClient() follows redirects while its custom transport accepts the host from the redirected request URL when the port is the workspace agent HTTP API port 4. An authenticated user who controls a modified workspace agent and knows another online agent's UUID can derive the victim's tailnet address and redirect control-plane requests to that agent. HTTP 301, 302, and 303 redirects can redirect read requests, while HTTP 307 and 308 preserve replayable write and process-start requests. The redirected workspace agent file APIs can read or write files as the victim workspace user, and affected versions exposing the workspace agent process API can execute commands after a redirected file write, crossing workspace and tenant boundaries. This issue is fixed in versions 2.29.19, 2.32.9, 2.33.10, and 2.34.4.

CVSS v3
8.3
EG Score
8.3(medium)
EG Risk
38(Track)
EG Risk 38/100SSVC: 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
Severity83% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
36%
KEV
Not listed

Published

September 15, 2026

Last Modified

September 15, 2026

Advisory Details (10)

Auto-updated Sep 15, 2026
Patch available. Sources: github, github_pr, github_commit.
github_commit

commit eeb2624549dd (coder/coder)

Fix landed in coder/coder commit eeb2624549dd — awaiting tagged release

https://github.com/coder/coder/commit/eeb2624549ddb85538e493af3e678fdb185a809f
github_commit

commit ec3ba84c0002 (coder/coder)

Fix landed in coder/coder commit ec3ba84c0002 — awaiting tagged release

https://github.com/coder/coder/commit/ec3ba84c0002f47dd979c073cde1ab345acbaea5
github_commit

commit 812549d671d0 (coder/coder)

Fix landed in coder/coder commit 812549d671d0 — awaiting tagged release

https://github.com/coder/coder/commit/812549d671d0f5a0b45adcee860d37b70aaddccd
github_commit

commit 2312b67bc52c (coder/coder)

Fix landed in coder/coder commit 2312b67bc52c — awaiting tagged release

https://github.com/coder/coder/commit/2312b67bc52c4e314c18c4b4be5dcf5500c94ad7
github_pr

fix: pin workspace agent API client to intended agent (#26600)

Fix merged in coder/coder PR #26622 on 2026-06-27 — awaiting tagged release

https://github.com/coder/coder/pull/26622
github_pr

fix: pin workspace agent API client to intended agent (#26600)

Fix merged in coder/coder PR #26613 on 2026-06-27 — awaiting tagged release

https://github.com/coder/coder/pull/26613
github_pr

fix: pin workspace agent API client to intended agent (#26600)

Fix merged in coder/coder PR #26612 on 2026-06-27 — awaiting tagged release

https://github.com/coder/coder/pull/26612
github_pr

fix: pin workspace agent API client to intended agent (#26600)

Fix merged in coder/coder PR #26611 on 2026-06-27 — awaiting tagged release

https://github.com/coder/coder/pull/26611
github_pr

fix: pin workspace agent API client to intended agent

Fix merged in coder/coder PR #26600 on 2026-06-23 — awaiting tagged release

https://github.com/coder/coder/pull/26600
github Patch Available

Workspace agent API insecure redirect handling allowed cross-agent file read and write · Advisory · coder/coder · GitHub

https://github.com/coder/coder/security/advisories/GHSA-qrwj-vh9x-gw5v

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 12× 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. 2026-09-20 20:31 UTCEG score recompute
  2. 2026-09-20 20:16 UTCEPSS rescore
  3. 2026-09-19 20:08 UTCEG score recompute
  4. 2026-09-18 19:45 UTCEG score recompute
  5. 2026-09-18 19:28 UTCEPSS rescore
  6. 2026-09-18 07:33 UTCEG score recompute
  7. 2026-09-16 18:57 UTCEG score recompute
  8. 2026-09-16 14:08 UTCEPSS rescore
  9. 2026-09-15 18:33 UTCEG score recompute
  10. 2026-09-15 17:32 UTCEG score recompute
  11. 2026-09-15 16:53 UTCEG score recompute
  12. 2026-09-15 16:52 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-63443?
CVE-2026-63443 is a high vulnerability published on September 15, 2026. Coder allows organizations to provision remote development environments via Terraform. Prior to 2.29.19, 2.32.9, 2.33.10, and 2.34.4, agentConn.apiClient() follows redirects while its custom transport accepts the host from the redirected request URL when the port is the workspace agent HTTP API…
When was CVE-2026-63443 disclosed?
CVE-2026-63443 was first published in the National Vulnerability Database on September 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-63443 actively exploited?
CVE-2026-63443 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 63.8% of all scored CVEs.
What is the CVSS score of CVE-2026-63443?
CVE-2026-63443 has a CVSS v3 base score of 8.3 (NVD).
How do I remediate CVE-2026-63443?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-63443, 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.

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