diff --git a/Cargo.lock b/Cargo.lock
index 8ce6d68..19bbbea 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -104,12 +104,6 @@ dependencies = [
  "generic-array",
 ]
 
-[[package]]
-name = "bumpalo"
-version = "3.13.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a3e2c3daef883ecc1b5d58c15adae93470a91d425f3532ba1695849656af3fc1"
-
 [[package]]
 name = "byteorder"
 version = "1.4.3"
@@ -553,15 +547,6 @@ version = "1.0.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "af150ab688ff2122fcef229be89cb50dd66af9e01a4ff320cc137eecc9bacc38"
 
-[[package]]
-name = "js-sys"
-version = "0.3.64"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c5f195fe497f702db0f318b07fdd68edb16955aed830df8363d837542f8f935a"
-dependencies = [
- "wasm-bindgen",
-]
-
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
@@ -570,9 +555,9 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
-version = "0.2.147"
+version = "0.2.150"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b4668fb0ea861c1df094127ac5f1da3409a82116a4ba74fca2e58ef927159bb3"
+checksum = "89d92a4743f9a61002fae18374ed11e7973f530cb3a3255fb354818118b2203c"
 
 [[package]]
 name = "linked-hash-map"
@@ -947,17 +932,16 @@ checksum = "dbb5fb1acd8a1a18b3dd5be62d25485eb770e05afb408a9627d14d451bae12da"
 
 [[package]]
 name = "ring"
-version = "0.16.20"
+version = "0.17.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3053cf52e236a3ed746dfc745aa9cacf1b791d846bdaf412f60a8d7d6e17c8fc"
+checksum = "fb0205304757e5d899b9c2e448b867ffd03ae7f988002e47cd24954391394d0b"
 dependencies = [
  "cc",
+ "getrandom",
  "libc",
- "once_cell",
  "spin",
  "untrusted",
- "web-sys",
- "winapi",
+ "windows-sys 0.48.0",
 ]
 
 [[package]]
@@ -989,31 +973,30 @@ dependencies = [
 
 [[package]]
 name = "rustls"
-version = "0.21.7"
+version = "0.21.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cd8d6c9f025a446bc4d18ad9632e69aec8f287aa84499ee335599fabd20c3fd8"
+checksum = "446e14c5cda4f3f30fe71863c34ec70f5ac79d6087097ad0bb433e1be5edf04c"
 dependencies = [
  "log",
  "ring",
- "rustls-webpki 0.101.4",
+ "rustls-webpki",
  "sct",
 ]
 
 [[package]]
-name = "rustls-webpki"
-version = "0.100.2"
+name = "rustls-pemfile"
+version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e98ff011474fa39949b7e5c0428f9b4937eda7da7848bbb947786b7be0b27dab"
+checksum = "2d3987094b1d07b653b7dfdc3f70ce9a1da9c51ac18c1b06b662e4f9a0e9f4b2"
 dependencies = [
- "ring",
- "untrusted",
+ "base64",
 ]
 
 [[package]]
 name = "rustls-webpki"
-version = "0.101.4"
+version = "0.101.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7d93931baf2d282fff8d3a532bbfd7653f734643161b87e3e01e59a04439bf0d"
+checksum = "8b6275d1ee7a1cd780b64aca7726599a1dbc893b1e64144529e55c3c2f745765"
 dependencies = [
  "ring",
  "untrusted",
@@ -1051,9 +1034,9 @@ checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
 
 [[package]]
 name = "sct"
-version = "0.7.0"
+version = "0.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d53dcdb7c9f8158937a7981b48accfd39a43af418591a5d008c7b22b5e1b7ca4"
+checksum = "da046153aa2352493d6cb7da4b6e5c0c057d8a1d0a9aa8560baffdd945acd414"
 dependencies = [
  "ring",
  "untrusted",
@@ -1156,9 +1139,9 @@ checksum = "62bb4feee49fdd9f707ef802e22365a35de4b7b299de4763d44bfea899442ff9"
 
 [[package]]
 name = "spin"
-version = "0.5.2"
+version = "0.9.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6e63cff320ae2c57904679ba7cb63280a3dc4613885beafb148ee7bf9aa9042d"
+checksum = "6980e8d7511241f8acf4aebddbb1ff938df5eebe98691418c4468d0b72a96a67"
 
 [[package]]
 name = "static_assertions"
@@ -1398,15 +1381,15 @@ checksum = "c0edd1e5b14653f783770bce4a4dabb4a5108a5370a5f5d8cfe8710c361f6c8b"
 
 [[package]]
 name = "untrusted"
-version = "0.7.1"
+version = "0.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a156c684c91ea7d62626509bce3cb4e1d9ed5c4d978f7b4352658f96a4c26b4a"
+checksum = "8ecb6da28b8a351d773b68d5825ac39017e680750f980f3a1a85cd8dd28a47c1"
 
 [[package]]
 name = "ureq"
-version = "2.7.1"
+version = "2.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0b11c96ac7ee530603dcdf68ed1557050f374ce55a5a07193ebf8cbc9f8927e9"
+checksum = "f5ccd538d4a604753ebc2f17cd9946e89b77bf87f6a8e2309667c6f2e87855e3"
 dependencies = [
  "base64",
  "flate2",
@@ -1414,7 +1397,7 @@ dependencies = [
  "native-tls",
  "once_cell",
  "rustls",
- "rustls-webpki 0.100.2",
+ "rustls-webpki",
  "url",
  "webpki-roots",
 ]
@@ -1486,78 +1469,11 @@ version = "0.11.0+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
 
-[[package]]
-name = "wasm-bindgen"
-version = "0.2.87"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7706a72ab36d8cb1f80ffbf0e071533974a60d0a308d01a5d0375bf60499a342"
-dependencies = [
- "cfg-if",
- "wasm-bindgen-macro",
-]
-
-[[package]]
-name = "wasm-bindgen-backend"
-version = "0.2.87"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5ef2b6d3c510e9625e5fe6f509ab07d66a760f0885d858736483c32ed7809abd"
-dependencies = [
- "bumpalo",
- "log",
- "once_cell",
- "proc-macro2",
- "quote",
- "syn",
- "wasm-bindgen-shared",
-]
-
-[[package]]
-name = "wasm-bindgen-macro"
-version = "0.2.87"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dee495e55982a3bd48105a7b947fd2a9b4a8ae3010041b9e0faab3f9cd028f1d"
-dependencies = [
- "quote",
- "wasm-bindgen-macro-support",
-]
-
-[[package]]
-name = "wasm-bindgen-macro-support"
-version = "0.2.87"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "54681b18a46765f095758388f2d0cf16eb8d4169b639ab575a8f5693af210c7b"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
- "wasm-bindgen-backend",
- "wasm-bindgen-shared",
-]
-
-[[package]]
-name = "wasm-bindgen-shared"
-version = "0.2.87"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ca6ad05a4870b2bf5fe995117d3728437bd27d7cd5f06f13c17443ef369775a1"
-
-[[package]]
-name = "web-sys"
-version = "0.3.64"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9b85cbef8c220a6abc02aefd892dfc0fc23afb1c6a426316ec33253a3877249b"
-dependencies = [
- "js-sys",
- "wasm-bindgen",
-]
-
 [[package]]
 name = "webpki-roots"
-version = "0.23.1"
+version = "0.25.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b03058f88386e5ff5310d9111d53f48b17d732b401aeb83a8d5190f2ac459338"
-dependencies = [
- "rustls-webpki 0.100.2",
-]
+checksum = "14247bb57be4f377dfb94c72830b8ce8fc6beac03cf4bf7b9732eadd414123fc"
 
 [[package]]
 name = "winapi"
@@ -1751,6 +1667,8 @@ dependencies = [
  "parking_lot",
  "rayon",
  "regex",
+ "rustls",
+ "rustls-pemfile",
  "serde",
  "serde_json",
  "sha2",
diff --git a/Cargo.toml b/Cargo.toml
index a45c9a1..86ba095 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,7 +16,7 @@ default = ["rustls-tls"]
 rustls-tls = ["ureq/tls"]
 # If this feature is enabled we instead use the native TLS implementation for the
 # target platform
-native-tls = ["ureq/native-tls", "native-tls-crate/vendored"]
+native-tls = ["ureq/native-tls", "native-tls-crate/vendored", "rustls-pemfile", "rustls"]
 
 [dependencies]
 # Easy errors
@@ -47,6 +47,9 @@ regex = "1.0"
 ureq = { version = "2.4", default-features = false, features = ["gzip"] }
 memchr = "2.6"
 native-tls-crate = { package = "native-tls", version = "0.2", optional = true }
+# CA Cert for HTTP requests
+rustls = { version = "0.21.8", optional = true }
+rustls-pemfile = { version = "1.0.3", optional = true }
 # SHA-256 verification
 sha2 = "0.10"
 # Deserialization
diff --git a/deny.toml b/deny.toml
index 4dd3b93..14cf700 100644
--- a/deny.toml
+++ b/deny.toml
@@ -43,8 +43,6 @@ skip = [
   { name = "regex-syntax", version = "=0.6.29" },
   # ditto :(
   { name = "regex-automata", version = "=0.1.10" },
-  # ureq
-  { name = "rustls-webpki", version = "=0.100.2" },
 ]
 skip-tree = [
   # clap -> terminal_size
diff --git a/src/ctx.rs b/src/ctx.rs
index 21160a7..cfd62ad 100644
--- a/src/ctx.rs
+++ b/src/ctx.rs
@@ -27,11 +27,24 @@ pub struct Ctx {
 impl Ctx {
     fn http_client(read_timeout: Option<Duration>) -> Result<ureq::Agent, Error> {
         let mut builder = ureq::builder();
-
         #[cfg(feature = "native-tls")]
         {
+            use std::env;
+            use std::fs::File;
+            use std::io::BufReader;
             use std::sync::Arc;
-            builder = builder.tls_connector(Arc::new(native_tls_crate::TlsConnector::new()?));
+
+            let mut tls_builder = native_tls_crate::TlsConnector::builder();
+            if let Some(custom_ca) =
+                env::var_os("REQUESTS_CA_BUNDLE").or_else(|| env::var_os("CURL_CA_BUNDLE"))
+            {
+                let mut reader = BufReader::new(File::open(custom_ca)?);
+                for cert in rustls_pemfile::certs(&mut reader)? {
+                    tls_builder
+                        .add_root_certificate(native_tls_crate::Certificate::from_pem(&cert)?);
+                }
+            }
+            builder = builder.tls_connector(Arc::new(tls_builder.build()?));
         }
 
         // Allow user to specify timeout values in the case of bad/slow proxies