EEF-CVE-2026-48596 CVE-2026-48596 GHSA-q7jx-v53g-848w
CRLF injection in Tesla.Multipart.add_content_type_param/2 allows HTTP header injection
- Severity
- 0.0 / 10
- Low · CVSS 4.0
- Exploit chance (EPSS)
- 0.24%
- Chance of exploitation in the next 30 days. Higher than 15.04% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')
- Fix
1.18.3- Upgrade tesla to this version or later
Description
Summary
Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') vulnerability in elixir-tesla tesla allows HTTP header injection via Tesla.Multipart.add_content_type_param/2.
Tesla.Multipart.add_content_type_param/2 appends caller-supplied strings to the multipart content_type_params list without validating for CR (\r) or LF (\n) characters. Tesla.Multipart.headers/1 then joins these params verbatim with "; " to construct the outgoing Content-Type header value. A param containing \r\n splits the header line, allowing arbitrary headers to be injected into the outbound HTTP request. Any application that forwards untrusted input (such as a user-supplied charset or parameter string) into add_content_type_param/2 is affected.
This issue affects tesla: from 0.8.0 before 1.18.3.
Workarounds
Validate content-type parameter strings before passing them to Tesla.Multipart.add_content_type_param/2, rejecting any value that contains \r or \n.
Configurations
The application must pass untrusted input into Tesla.Multipart.add_content_type_param/2.
Affected versions
Hex
| Package | Vulnerable | Fixed in |
|---|---|---|
| tesla | >= 0.8.0, < 1.18.3 |
1.18.3 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
tesla Hex → 1.18.3
- mix
{:tesla, "~> 1.18.3"} # then: mix deps.update tesla
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N
- Attack vector
- Local
- Attack complexity
- Low
- Attack requirements
- Present
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- Low
- Availability (subsequent systems)
- None
CVSS 3.1 3.7
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Weakness
CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')
The product receives data from an HTTP agent/component (e.g., web server, proxy, browser, etc.), but it does not neutralize or incorrectly neutralizes CR and LF characters before the data is included in outgoing HTTP headers.
How to prevent it
- Implementation: Construct HTTP headers very carefully, avoiding the use of non-validated input data.
- Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. If an input does not strictly conform to specifications, reject it or transform it into something that conforms. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
- Implementation: Use and specify an output encoding that can be handled by the downstream component that is reading the output. Common encodings include ISO-8859-1, UTF-7, and UTF-8. When an encoding is not specified, a downstream component may choose a different encoding, either by assuming a default encoding or automatically inferring which encoding is being used, which can be erroneous. When the encodings are inconsistent, the downstream component might treat some character or byte sequences as special, even if they are not special in the original encoding. Attackers might then be able to exploit this discrepancy and conduct injection attacks; they even might be able to bypass protection mechanisms that assume the original encoding is also being used by the downstream component.
- Implementation: Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
References
Advisories
Fixes and patches
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| EEF-CVE-2026-48594 Decompression bomb in Tesla.Middleware.DecompressResponse and Tesla.Middleware.Compression | High | Also affects tesla |
| EEF-CVE-2026-48595 Authorization header leaks to third-party origin on cross-origin redirect in Tesla.Middleware.FollowRedirects | Medium | Also affects tesla |
| EEF-CVE-2026-48597 Atom table exhaustion via untrusted URL scheme in Tesla.Adapter.Mint | Medium | Also affects tesla |
| GHSA-28jh-g32x-v9v4 CRLF injection in Tesla.Multipart disposition parameters allows multipart part header injection | Low | Also affects tesla |
| EEF-CVE-2026-112880 CRLF injection in Proxy-Authorization header built from proxy_auth_fun in hackney | Not rated yet | Same weakness, CWE-113 |
| GHSA-4v4h-m2qq-ppgw Kirby: Request header injection in `Http\Remote` | Medium | Same weakness, CWE-113 |
| GHSA-m6qw-4cw2-hm4m aiohttp: CRLF injection in multipart headers | High | Same weakness, CWE-113 |
| EEF-CVE-2026-43966 HTTP Response Splitting via Non-VCHAR Bytes in cow_http_struct_hd:escape_string/2 | Medium | Same weakness, CWE-113 |
Credits: Jonatan Männchen / EEF, Peter Ullrich, Yordis Prieto
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