vulnerability / NVI-00009115 / Revision 5
i18next-http-backend: Query-parameter injection through & and = in lng when loadPath/addPath puts {{lng}} in the query string
GitHub lists this reviewed advisory for i18next-http-backend. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
3.7 low
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
3.7 LOW (3.1)
security-advisories@github.com severity; no combined Null risk score.
0.280%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.20572. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
i18next-http-backend
source listed< 4.0.4
### Summary The URL-segment check added for GHSA-q89c-q3h5-w34g blocks `?`, `#`, `%`, `:`, `/` and `@` in `lng`, but not `&` or `=`, and the checked value is inserted into the URL without encoding. The README documents a multiload loadPath of the form `/locales/resources.json?lng=de+en&ns=ns1+ns2`. With a template like that, an attacker who controls the language value can add or override query parameters on the request the backend sends. By default the language comes from `?lng=`, a cookie or `Accept-Language`. This is the "query-string injection" impact described in GHSA-q89c; only the `?` form was closed. Server side (Express + i18next-http-middleware, default options), `GET /?lng=de%26ns%3Dprivate%26admin%3Dtrue` makes the application request `…?lng=de&ns=private&admin=true&ns=common` from its own translations API. ### Details The checks are in `lib/utils.js`. The base check (https://github.com/i18next/i18next-http-backend/blob/v4.0.3/lib/utils.js#L26-L44) rejects: - empty or >128-character values and prototype keys; - `..` and `\`; - `/[?#%:\s]/`; - control characters. `isSafeLangUrlSegment` (https://github.com/i18next/i18next-http-backend/blob/v4.0.3/lib/utils.js#L51-L55
i18next-http-backend
source listedSEMVER: introduced 0; fixed 4.0.4
### Summary The URL-segment check added for GHSA-q89c-q3h5-w34g blocks `?`, `#`, `%`, `:`, `/` and `@` in `lng`, but not `&` or `=`, and the checked value is inserted into the URL without encoding. The README documents a multiload loadPath of the form `/locales/resources.json?lng=de+en&ns=ns1+ns2`. With a template like that, an attacker who controls the language value can add or override query parameters on the request the backend sends. By default the language comes from `?lng=`, a cookie or `Accept-Language`. This is the "query-string injection" impact described in GHSA-q89c; only the `?` form was closed. Server side (Express + i18next-http-middleware, default options), `GET /?lng=de%26ns%3Dprivate%26admin%3Dtrue` makes the application request `…?lng=de&ns=private&admin=true&ns=common` from its own translations API. ### Details The checks are in `lib/utils.js`. The base check (https://github.com/i18next/i18next-http-backend/blob/v4.0.3/lib/utils.js#L26-L44) rejects: - empty or >128-character values and prototype keys; - `..` and `\`; - `/[?#%:\s]/`; - control characters. `isSafeLangUrlSegment` (https://github.com/i18next/i18next-http-backend/blob/v4.0.3/lib/utils.js#L51-L55
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
- vendor patch
The original advisory lists fixed boundaries 4.0.4 for i18next-http-backend. Confirm the publisher’s latest guidance.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database via OSV
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
- NVD lastModified does not establish freshness of every associated CPE record.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-3cmx-xjww-583x ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- GHSA-3cmx-xjww-583x ↗
GitHub Advisory Database via OSV · vendor advisory
Observed . GitHub-origin advisory, CC-BY-4.0; OSV is an aggregate copy, not independent corroboration.
- CVE-2026-118258 ↗
NIST National Vulnerability Database · official catalog
Observed . This product uses data from the NVD API but is not endorsed or certified by the NVD.
- CVE-2026-118258 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 5 ·
Source facts changed; compare the preserved prior revision.
- Revision 4 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 3 ·
Source facts changed; compare the preserved prior revision.
- Revision 2 ·
Source facts changed; compare the preserved prior revision.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.